JP2016149788A - Propagation delay difference reporting for multiple component carriers - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide methods for reporting on downlink timing by a mobile terminal in a mobile communication system in order to allow an aggregation access point to obtain information on propagation delay differences of downlink transmissions on aggregated serving cells.SOLUTION: The mobile terminal performs measurement regarding transmission and/or reception time differences on a target/reference cell, and reports it to the eNodeB. The eNodeB compares the measurement result to a predefined maximum propagation delay time difference. Alternatively, the mobile terminal performs the measurement, compares it to the predefined maximum propagation delay time difference and then report the comparison result to the eNodeB.SELECTED DRAWING: Figure 36

Description

  The present invention relates to a method for reporting on downlink timing by a mobile terminal in a mobile communication system. The present invention is also to provide an apparatus and system for performing the methods described herein, and a computer readable medium with instructions that cause the apparatus and system to perform the methods described herein.

Long Term Evolution (LTE)
Third generation mobile systems (3G) based on WCDMA® wireless access technology are being widely deployed throughout the world. The first step to advance or evolve this technology is the introduction of high-speed downlink packet access (HSDPA) and enhanced uplink, also known as high-speed uplink packet access (HSUPA), which is highly advantageous You need to provide wireless access technology.

  In order to prepare for increasing user demand and to dominate new radio access technologies, 3GPP has introduced a new mobile communication system called Long Term Evolution (LTE). LTE is designed to meet the needs of carriers for high-speed data and media transfer and high-capacity voice support for the next decade. The ability to provide high bit rates is an important measure of LTE.

  Evolved UMTS Terrestrial Radio Access (UTRA) and UMTS Terrestrial Radio Access Network (UTRAN) (Evolved UMTS Terrestrial Radio Access) The specification of the item (WI) will be summarized as Release 8 (LTE Rel. 8). The LTE system represents an efficient packet-based radio access and radio access network that provides fully IP-based functionality with low latency and low cost. In LTE, scalable systems such as 1.4, 3.0, 5.0, 10.0, 15.0, and 20.0 MHz are implemented to achieve flexible system deployment using a given spectrum. Multiple transmission bandwidths are defined. In the downlink, radio access based on direct frequency division multiplexing (OFDM) has its inherent immunity to multipath interference (MPI) due to its low symbol rate, the use of cyclic prefix (CP), and Adopted for its affinity to various transmission bandwidth configurations. Radio access based on single carrier frequency division multiple access (SC-FDMA) provides peak data rate by providing wide area coverage given the limited transmit power of user equipment (UE) Since it was prioritized, it was adopted on the uplink. Many important packet radio access technologies, including multiple-input multiple-output (MIMO) channel transmission technology, are used, and a highly efficient control signaling structure is developed in LTE Rel. Realized in 8/9.

LTE Architecture The overall architecture is shown in FIG. 1, and a more detailed representation of the E-UTRAN architecture is given in FIG. The E-UTRAN consists of an eNodeB that provides E-UTRA user plane (PDCP / RLC / MAC / PHY) and control plane (RRC) protocol termination to user equipment (UE). eNodeB (eNB) hosts packet data control protocol (PDCP) layer including physical (PHY), medium access control (MAC), radio link control (RLC), and user plane header compression and encryption functions To do. The eNodeB (eNB) also provides a radio resource control (RRC) function corresponding to the control plane. eNodeB (eNB) performs radio resource management, admission control, scheduling, enforcement of negotiated uplink quality of service (QoS), broadcast of cell information, encryption / decryption of user and control plane data And perform many functions, including compression / decompression of downlink / uplink user plane packet headers. The eNodeBs are connected to each other by an X2 interface.

  The eNodeB is in the EPC (Evolved Packet Core) via the S1 interface, more specifically in the MME (Mobility Management Entity) via the S1-MME and to the Serving Gateway (SGW) via the S1-U. Is also connected. The S1 interface supports a many-to-many relationship between the MME / serving gateway and the eNodeB. The SGW as a user plane mobility anchor during inter-eNodeB handover and between LTE and other 3GPP technologies (terminating the S4 interface and relaying traffic between the 2G / 3G system and the PDN GW) It also routes and forwards user data packets, acting as an anchor for mobility. For idle user equipment, the SGW terminates the downlink data path and triggers paging when downlink data arrives for that user equipment. The SGW manages and stores the context of user equipment, for example, IP bearer service parameters and routing information inside the network. The SGW also replicates user traffic during a lawful intercept.

  The MME is an important control node for the LTE access network. The MME is responsible for idle mode user equipment tracking and paging procedures including retransmissions. The MME is involved in the bearer activation / deactivation process, and also selects the SGW for the user equipment at the first attach and during intra-LTE handover with core network (CN) node relocation. Take a role. The MME is responsible for authenticating the user (by interacting with the HSS). Non-access layer (NAS) signaling ends at the MME, which is also responsible for generating temporary identification information and assigning it to user equipment. The MME examines the user equipment's authority to camp on the service provider's Public Land Mobile Network (PLMN) and enforces roaming restrictions on the user equipment. The MME is a termination point in the network for encryption / integrity protection for NAS signaling and handles security key management. Lawful interception of signaling is also supported by the MME. The MME also provides a control plane function for mobility between LTE and 2G / 3G access networks via an S3 interface ending in the MME from the SGSN. The MME also terminates the S6a interface to the home HSS for user equipment roaming.

L1 / 2 control signaling L1 / L2 control signaling of transport format and other data related information (eg HARQ) is reported on the downlink to inform the scheduled users about their user assignment status Must be sent with the data. Control signaling needs to be multiplexed with downlink data in subframes (assuming user assignments can change from subframe to subframe). It should be noted here that user assignment may be performed based on TTI (Transmission Time Interval) and TTI length may be a multiple of a subframe. The TTI length can be fixed in the service area for all users, can be different for different users, or even dynamic for each user. In general, then, the L1 / 2 control signaling needs to be sent only once per TTI. L1 / L2 control signaling is transmitted on the physical downlink control channel (PDCCH). Note that allocations for UL data transmission, UL grants are also transmitted on the PDCCH.

In general, information transmitted by L1 / L2 control signaling is divided into the following two categories.
Shared control information (SCI) that carries Cat1 information. The SCI portion of L1 / L2 control signaling includes information related to resource allocation (indication). The SCI typically includes the following information:
-User identification information indicating a user to be allocated-RB allocation information indicating a resource (resource block, RB) to which the user is allocated. Note that the number of RBs to which a user is assigned can be dynamic.
○ Arbitrary: If allocation across multiple subframes (TTI) is possible, duration of allocation

Depending on the setting of other channels and the setting of dedicated control information (DCI), the SCI further includes information such as ACK / NACK related to uplink transmission, uplink scheduling information, information related to DCI (resources, MCS, etc.) May be included.
● Individual control information (DCI) that carries Cat2 / 3 information

The DCI part of the L1 / L2 control signaling contains information related to the transmission format (Cat2) of the data sent to the scheduled user indicated by Cat1. Further, when (hybrid) ARQ is applied, the DCI portion of the L1 / L2 control signaling carries HARQ (Cat3) information. The DCI needs to be decoded only by users scheduled according to Cat1. Typically, DCI includes information regarding:
Cat2: Modulation method, transport block (payload) size (or coding rate), information on MIMO, etc. Cat3: Information related to HARQ, for example, hybrid ARQ process number, redundancy version (redundancy version), retransmission sequence number

  In the following, detailed L1 / L2 control signaling information signaled for DL allocation and uplink allocation is described below.

Downlink data transmission:
Along with the transmission of downlink packet data, L1 / L2 control signaling is transmitted on a separate physical channel (PDCCH). Typically, this L1 / L2 control signaling includes information regarding:

  The physical resource (s) (eg, subcarrier or subcarrier block for OFDM, code for CDMA) over which data is transmitted. This information allows the UE (receiver) to identify the resource on which the data is transmitted.

  O The transport format used for transmission. This may be the data transport block size (payload size, information bit size), MCS (modulation and coding scheme) level, spectral efficiency, coding rate, etc. This information (usually with resource allocation) allows the UE (receiver) to specify the information bit size, modulation scheme, and coding rate to initiate the demodulation, de-rate matching, and decoding processes Enable. In some cases, the modulation scheme may be explicitly signaled.

○ Hybrid ARQ (HARQ) information:
● Process number: allows the UE to identify the hybrid ARQ process to which the data is mapped ● Sequence number or new data indicator: UE identifies whether the transmission is a new packet or a retransmission packet Redundancy and / or constellation version: which hybrid ARQ redundancy version is used (required for de-rate matching) and / or which modulation signal Tell the UE whether a point placement version is used (required for demodulation)

  UE identification information (UE ID): Informs which UE is targeted by L1 / L2 control signaling. In a typical implementation, this information is used to mask the CRC of L1 / L2 control signaling to prevent other UEs from reading this information.

Uplink data transmission:
To allow transmission of uplink packet data, L1 / L2 control signaling is sent on the downlink (PDCCH) to inform the UE about the details of the transmission. Typically, this L1 / L2 control signaling includes information regarding:

  The physical resource (s) to which the UE is to transmit data (eg subcarrier or subcarrier block for OFDM, code for CDMA).

  O The transport format that the UE should use for transmission. This may be the data transport block size (payload size, information bit size), MCS (modulation and coding scheme) level, spectral efficiency, coding rate, etc. This information (usually with resource allocation) allows the UE (transmitter) to select the information bit size, modulation scheme, and coding rate to initiate the modulation, rate matching, and coding process. to enable. In some cases, the modulation scheme may be explicitly signaled.

○ Hybrid ARQ information:
Process number: Tells the UE from which hybrid ARQ process the UE should get data Sequence number or new data indicator: Instructs the UE to send a new packet or retransmit the packet Redundant and / or constellation version: which hybrid ARQ redundancy version should be used (required for rate matching) and / or which modulation constellation version should be used (required for demodulation) Tell the UE

  UE identification information (UE ID): Tells which UE should transmit data. In a typical implementation, this information is used to mask the CRC of L1 / L2 control signaling to prevent other UEs from reading this information.

There are a number of different features in how to accurately transmit the above information. Further, the L1 / L2 control information may include additional information or a part of the information may be omitted. For example:
● HARQ process number may not be required for synchronous HARQ protocol ● Redundancy and / or constellation version, if chase synthesis is used (always the same redundancy and / or constellation version) Or if the order of redundant and / or constellation versions is predefined, it may not be required.
● Power control information may be additionally included in control signaling. ● For example, control information related to MIMO such as precoding may be additionally included in control signaling.
For multi-codeword MIMO transmission, transport format and / or HARQ information for multiple codewords may be included

  For uplink resource allocation (PUSCH) signaled on PDCCH in LTE, the L1 / L2 control information does not include the HARQ process number because the synchronous HARQ protocol is used for the LTE uplink. The HARQ process to be used for uplink transmission is given by the timing. Furthermore, it is noted that redundant version (RV) information is encoded in conjunction with transport format information, ie, RV information is embedded in a transport format (TF) field. The TF or MCS field has a size of 5 bits corresponding to 32 entries, for example. Three TF / MCS table entries are reserved to indicate RV1, 2, or 3. The remaining MCS table entries are used to signal an MCS level (TBS) that implicitly indicates RV0. The size of the CRC field of the PDCCH is 16 bits. More detailed information regarding control information for uplink resource allocation on PUSCH can be found in TS36.212 section 5.3.3 and TS36.213 section 8.6.

  For downlink allocation (PDSCH) signaled on PDCCH in LTE, the redundancy version (RV) is signaled separately in a 2-bit field. In addition, modulation order information is encoded along with transport format information. Similar to the uplink case, there is a 5-bit MCS field signaled on the PDCCH. Three of the entries are reserved for signaling explicit modulation orders and do not provide transport format (transport block) information. For the remaining 29 entries, modulation order and transport block size information is signaled. More detailed information regarding control information for uplink resource allocation on PUSCH can be found in TS36.212 section 5.3.3 and TS36.213 section 7.1.7.

個のサブキャリア上で送信されるいくつかの変調シンボルからなる。 LTE (Release 8) Component Carrier Structure 3GPP LTE (Release 8) downlink component carriers are so-called subframes, which are subdivided in the time-frequency domain. In 3GPP LTE (Release 8), each subframe is divided into two downlink slots as shown in FIG. 3, and the first downlink slot is the control channel region ( PDCCH region). Each subframe consists of a given number of OFDM symbols in the time domain (12 or 14 OFDM symbols in 3GPP LTE (Release 8)), each of which spans the entire bandwidth of the component carrier. . Thus, each OFDM symbol has its respective symbol, as also shown in FIG.

It consists of several modulation symbols transmitted on subcarriers.

個の連続するＯＦＤＭシンボルとして定義され、周波数ドメインにおいて

個の連続するサブキャリアとして定義される。したがって、３ＧＰＰ ＬＴＥ（リリース８）において、物理リソース・ブロックは、時間ドメインにおける１スロットおよび周波数ドメインにおける１８０ｋＨｚに対応する

個のリソース要素からなる（ダウンリンクのリソース・グリッドに関するさらなる詳細については、例えば、ｈｔｔｐ：／／ｗｗｗ．３ｇｐｐ．ｏｒｇにおいて入手可能であり、参照により本明細書に組み込まれる３ＧＰＰ ＴＳ３６．２１１、「Ｅｖｏｌｖｅｄ Ｕｎｉｖｅｒｓａｌ Ｔｅｒｒｅｓｔｒｉａｌ Ｒａｄｉｏ Ａｃｃｅｓｓ（Ｅ−ＵＴＲＡ）；Ｐｈｙｓｉｃａｌ Ｃｈａｎｎｅｌｓ ａｎｄ Ｍｏｄｕｌａｔｉｏｎ（リリース８）」、バージョン８．９．０または９．０．０、セクション６．２を参照されたい）。 For example, assuming a multi-carrier communication system that uses OFDM, for example, as used in 3GPP Long Term Evolution (LTE), the smallest unit of resources that can be allocated by the scheduler is one “resource block” . Physical resource blocks are in the time domain as illustrated in FIG.

Defined as consecutive OFDM symbols in frequency domain

Defined as consecutive subcarriers. Thus, in 3GPP LTE (Release 8), a physical resource block corresponds to 1 slot in the time domain and 180 kHz in the frequency domain

(For further details on the downlink resource grid, see, eg, 3GPP TS 36.211, available at http://www.3gpp.org and incorporated herein by reference, “ Evolved Universal Terrestrial Radio Access (E-UTRA); Physical Channels and Modulation (Release 8) ", version 8.9.0 or 9.0.0, see section 6.2).

  The term “component carrier” refers to a combination of several resource blocks. In future releases of LTE, the term “component carrier” will no longer be used, but instead the term will be changed to “cell”, which refers to a combination of downlink resources and optional uplink resources. . The link between the carrier frequency of the downlink resource and the carrier frequency of the uplink resource is indicated in the system information transmitted on the downlink resource.

Further progress of LTE (LTE-A)
The frequency spectrum for IMT-Advanced was determined at the World Radiocommunication Conference 2007 (WRC-07). Although the overall frequency spectrum for IMT-Advanced has been determined, the actual available frequency bandwidth varies from region to region or country. However, in accordance with the decision regarding the overview of the available frequency spectrum, standardization of the radio interface began with the 3rd Generation Partnership Project (3GPP). At the 3GPP TSG RAN # 39 meeting, it was approved to include considerations regarding “E-UTRA further advances (LTE-Advanced)”. The considerations include, for example, technical components to be considered for the evolution of E-UTRA to meet the requirements for IMT-Advanced. Two major technical components currently under consideration for LTE-A are described below.

Carrier aggregation in LTE-A to support wider bandwidth The bandwidth that an LTE-Advanced system can support is 100 MHz, but the LTE system can only support 20 MHz. Currently, the lack of radio spectrum has become a bottleneck in the development of radio networks, and as a result, it is difficult to find a sufficiently wide spectrum band for LTE-Advanced systems. Accordingly, there is an urgent need to find a way to obtain a wider radio spectrum band, and a possible answer is the carrier aggregation function.

  In carrier aggregation, two or more component carriers (component carriers) are aggregated to support a wider transmission bandwidth of up to 100 MHz. Several cells of the LTE system are aggregated into one wider channel of the LTE-Advanced system that is wide enough for 100 MHz, even though these cells of LTE are in different frequency bands.

  All component carriers are at least LTE Rel.1 when the aggregated number of component carriers in the uplink and downlink are the same. It can be configured to be compatible with 8/9. Not all component carriers that are aggregated by the user equipment are necessarily Rel. It is not compatible with 8/9. Existing mechanisms (eg, barring) can be used to prevent Rel-8 / 9 user equipment from camping on component carriers.

  A user equipment can receive or transmit one or more component carriers simultaneously (corresponding to multiple serving cells) depending on the capabilities of the user equipment. LTE-A Rel. With reception and / or transmission capability for carrier aggregation. Ten user equipments can receive and / or transmit simultaneously in multiple serving cells, but LTE Rel. In the 8/9 user equipment, the component carrier structure is Rel. As per the 8/9 specification, reception and transmission can be done with only a single serving cell.

In carrier aggregation, each component carrier is Rel. Supported for both continuous and discontinuous component carriers, using 8/9 numerology to limit to a maximum of 110 resource blocks in the frequency domain. In the uplink and downlink, user equipment can be configured to aggregate different numbers of component carriers that originate from the same eNodeB and possibly of different bandwidths.
The number of downlink component carriers that can be configured depends on the downlink aggregation capability of the user equipment.
The number of uplink component carriers that can be configured depends on the uplink aggregation capabilities of the user equipment.
-User equipment that uses more uplink component carriers than downlink component carriers may not be configured.
-In a typical TDD deployment, the number of component carriers in the uplink and downlink and the bandwidth of each component carrier are the same.

  Component carriers originating from the same eNodeB do not necessarily provide the same coverage.

  The spacing between the central frequencies of continuously aggregated component carriers is a multiple of 300 kHz. This is because Rel. This is because it is compatible with an 8/9 100 kHz frequency raster and at the same time maintains the orthogonality of subcarriers at 15 kHz intervals. Depending on the aggregation scenario, spacing of nx 300 kHz can be facilitated by inserting a small number of unused subcarriers between consecutive component carriers.

  The aggregation nature of multiple carriers is only revealed up to the MAC layer. There is one HARQ entity required in the MAC for each aggregated component carrier for both uplink and downlink. (For uplink-SU-MIMO-single user multiple input multiple output is not used) There is at most one transport block per component carrier. The transport block and its potential HARQ retransmission need to be mapped to the same component carrier. Layer 2 structures with enabled carrier aggregation are shown in FIGS. 5 and 6 for the downlink and uplink, respectively.

  When carrier aggregation is configured, the user equipment has only one RRC connection with the network. In establishing / re-establishing the RRC connection, one serving cell is associated with LTE Rel. As with 8/9, it provides security input (one ECGI, one PCI, and one ARFCN) and non-access layer mobility information (eg, TAI). After establishment / re-establishment of the RRC connection, the component carrier corresponding to that cell is called the downlink primary cell (P cell). There is always one and only one downlink P cell (DL P cell) and one uplink P cell (UL P cell) configured for each user equipment in connected mode. In the downlink, the carrier corresponding to the P cell is the downlink primary component carrier (DL PCC), while in the uplink, the carrier is the uplink primary component carrier (UL PCC). is there.

Depending on the capabilities of the user equipment, the secondary cell (S cell) may be configured to form a serving cell set with the P cell. Thus, a configured set of serving cells for user equipment always consists of one P cell and one or more S cells. The characteristics of the downlink and uplink P cells and S cells are:
-The uplink P-cell is used for transmission of Layer 1 uplink control information (PUCCH)-Unlike the S-cell, the downlink P-cell cannot be deactivated-The re-establishment is Triggered when a downlink P-cell suffers RLF rather than when an S-cell suffers Rayleigh Fading (RLF)-In addition to the use of downlink resources for each S-cell, uplink resources by the UE (Thus, the number of DL SCCs configured is always greater than or equal to the number of UL S cells, and any S cell can only be configured for use of uplink resources. Can not)
-From the UE point of view, each uplink resource belongs to only one serving cell-that the P cell can only be changed by handover procedure (ie by security key change and RACH procedure) -The number of serving cells that can be configured depends on the aggregation capabilities of the UE-Non-access layer information is obtained from downlink P cells.

  S cell reconfiguration, addition, and deletion may be performed by RRC. In an intra-LTE handover, the RRC may still add, delete, or reconfigure S cells for use with the handover destination P cell. When adding a new S-cell, dedicated RRC signaling is used to transmit all required system information of the S-cell, i.e., while in connected mode, the user equipment has broadcast system information Need not be obtained directly from the S cell.

  When carrier aggregation is configured, user equipment can be scheduled across multiple component carriers simultaneously, but at any given time at most one random access procedure should be in progress. Cross-carrier scheduling allows a component carrier physical downlink control channel (PDCCH) to schedule resources for another component carrier. For this purpose, a component carrier identification field (CIF) is introduced in each downlink control information (DCI) format. The link between the uplink component carrier and the downlink component carrier allows to identify the uplink component carrier that is granted permission when there is scheduling that does not cross carriers. The link of the downlink component carrier to the uplink component carrier does not necessarily have to be one to one. In other words, two or more downlink component carriers may link to the same uplink component carrier. At the same time, the downlink component carrier may only link to one uplink component carrier.

S cell activation / deactivation To enable reasonable UE battery consumption when CA is configured, an S cell activation / deactivation mechanism is supported (ie, activation / deactivation). Activation does not apply to P cells). When the S cell is deactivated, the UE does not need to receive the corresponding PDCCH or PDSCH, cannot transmit on the corresponding uplink, and is not required to perform CQI measurements. Conversely, when the S cell is active, the UE will receive PDSCH and PDCCH (if the UE is configured to monitor PDCCH from this S cell) and perform CQI measurement It is expected to be possible.

  The activation / deactivation mechanism is based on a combination of a MAC control element and a deactivation timer. The MAC control element carries a bitmap for S cell activation and deactivation, and a bit set to 1 represents activation of the corresponding S cell, while a bit set to 0 is inactive. Represents Bitmaps can be used to activate and deactivate S cells individually, and a single activation / deactivation command can activate / deactivate a subset of S cells. A corresponding activated / deactivated MAC CE is shown in FIG. Note that even though there are up to four S cells to which the UE can aggregate, the MAC CE contains seven entries, each corresponding to an S cell configured with SCellIndex i.

One deactivation timer is maintained for each S cell, but one common value is configured for each UE by RRC. In reconfiguration without using mobility control information,
O S-cells added to the serving cell set are initially "inactive".
O S-cells that remain in the serving cell set (either unchanged or reconfigured) do not change their S-cell activation state ("active" or "inactive").

In reconfiguration (ie, handover) using mobility control information,
O S cell is "deactivated".

LTE Uplink Access Scheme For uplink transmission, power efficient user terminal transmission is necessary to maximize coverage. Single carrier transmission combined with FDMA with dynamic bandwidth allocation was selected as the uplink transmission scheme for Evolved UTRA. The main reasons for favoring single carrier transmission are low peak-to-average power ratio (PAPR) compared to multi-carrier signal (OFDMA), as well as corresponding improved power amplifier efficiency and expected improved coverage (Higher data rate for the peak power of a given terminal). During each time interval, the NodeB allocates unique time / frequency resources for transmitting user data to the user, thereby ensuring orthogonality within the cell. Orthogonal access in the uplink ensures increased spectral efficiency by eliminating in-cell interference. Interference due to multipath propagation is handled at the base station (NodeB) with the help of inserting a cyclic prefix in the transmitted signal.

  The basic physical resource used for data transmission consists of a frequency resource of size BWgrant in one time interval, eg 0.5ms subframe, encoded into that basic physical resource Information bits are mapped. Note that a subframe, also referred to as a transmission time interval (TTI), is the minimum time interval for transmission of user data. However, by concatenating subframes, it is possible to allocate frequency resources BWgrant to users over a period longer than one TTI.

LTE Uplink Scheduling Scheme The uplink scheme allows both scheduled access, i.e., access controlled by the eNB and contention based access.

  For scheduled access, the UE is assigned a specific frequency resource (ie, time / frequency resource) for a specific time for uplink data transmission. However, some time / frequency resources may be allocated for contention based access. Among these time / frequency resources, the UE can transmit without first being scheduled. One scenario in which the UE has contention-based access is, for example, random access, ie, random access when the UE is making initial access to the cell, or requesting uplink resources For random access.

For scheduled access, the NodeB scheduler allocates unique frequency / time resources to users for uplink data transmission. More specifically, the scheduler
Which UE (s) are allowed to transmit,
○ Which physical channel resource (frequency)
-Transport format to be used by the mobile terminal for transmission (modulation coding scheme (MCS))
To decide.

  Allocation information is signaled to the UE with a scheduling grant sent on the L1 / L2 control channel. For simplicity, this channel is referred to below as the uplink grant channel. The scheduling grant message includes at least which part of the frequency band the UE is allowed to use, the validity period of the grant, and the transport format that the UE must use for the upcoming uplink transmission Contains information. The shortest valid period is one subframe. Depending on the scheme selected, additional information may be included in the authorization message. Only “per UE” grants are used to grant the right to transmit on the UL-SCH (ie, there is no “per UE RB” grant). Therefore, the UE needs to distribute the allocated resources among the radio bearers according to some rules, which will be explained in detail in the next section. Unlike HSUPA, there is no UE-based transport format selection. The eNB determines the transport format based on some information, eg, the reported scheduling information and QoS information, and the UE must follow the selected transport format. In HSUPA, the NodeB allocates the maximum uplink resources, and the UE accordingly selects the actual transport format for data transmission.

Since scheduling of radio resources is the most important function in a shared channel access network for determining quality of service, how many should be satisfied by the LTE UL scheduling scheme to enable efficient QoS management. There is such a requirement.
○ Starvation of low priority services must be avoided ○ Clear QoS distinction for radio bearers / services must be supported by the scheduling scheme ○ For which radio bearers / services the scheduler of the eNB is In order to be able to specify whether data should be transmitted, the UL report must allow for a granular buffer report (eg per radio bearer or per radio bearer group) Don't be.
○ It must be possible to make a clear QoS distinction between services of different users ○ It must be possible to provide a minimum bit rate per radio bearer

  As can be seen from the above list, one essential aspect of the LTE scheduling scheme is that the operator controls the partitioning of the capacity of the operator's aggregated cell between radio bearers of different QoS classes. It is to provide a mechanism that can. The radio bearer QoS class is specified by the QoS profile of the corresponding SAE bearer signaled from the AGW to the eNB as described above. The operator can then allocate a specific amount of the aggregated cell capacity of the operator to the aggregated traffic associated with a specific QoS class radio bearer. The main purpose of using this class-based approach is to be able to distinguish the processing of those packets according to the QoS class to which they belong.

Medium Access Control (MAC) and MAC Control Element The MAC layer is the lowest sublayer in the Layer 2 architecture of the LTE radio protocol stack (available at http://www.3gpp.org, in its entirety) 3GPP TS 36.321, “Medium Access Control (MAC) protocol specification”, version 8.7.0, specifically Sections 4.2, 4.3, 5.4.3, 6, which is incorporated herein by reference. See). Connection to the lower physical layer is made via the transport channel, and connection to the upper RLC layer is made via the logical channel. The MAC layer performs multiplexing and demultiplexing between the logical channel and the transport channel. The MAC layer of the transmitting side (user equipment in the following example) constitutes a MAC PDU, also called a transport block, from the MAC SDU received via the logical channel, and the MAC layer of the receiving side is the transport channel The MAC SDU is recovered from the MAC PDU received via.

  In a multiplexing and demultiplexing entity, data from several logical channels is multiplexed onto one transport channel and data to several logical channels is demultiplexed from one transport channel Is done. The multiplexing entity generates a MAC PDU from the MAC SDU when radio resources are available for a new transmission. This process includes prioritizing data from logical channels to determine how much data should be included in each MAC PDU from which logical channel. Note that in 3GPP terminology, the process of generating MAC PDUs at the user equipment is called logical channel prioritization (LCP).

  The demultiplexing entity reassembles MAC SDUs from the MAC PDUs and distributes them to the appropriate RLC entities. In addition, for peer-to-peer communication between MAC layers, control messages called “MAC control elements” can be included in the MAC PDU.

  A MAC PDU mainly consists of a MAC header and a MAC payload (see 3GPP TS36.321, section 6). The MAC header is further composed of a MAC subheader, while the MAC payload is composed of a MAC control element, a MAC SDU, and padding. Each MAC subheader includes a logical channel ID (LCID) and a length (L) field. The LCID indicates whether the corresponding part of the MAC payload is a MAC control element, and if not, indicates which logical channel the associated MAC SDU belongs to. The L field indicates the size of the associated MAC SDU or MAC control element. As already mentioned above, the MAC control element is the MAC level, including sending BSR information and UE available power report in the uplink, and sending DRX command and timing advance command in the downlink. Used for peer-to-peer signaling. One special LCID is assigned to each type of MAC control element. An example of a MAC PDU is shown in FIG.

Power control Uplink transmitter power control in a mobile communication system minimizes the need for transmitter energy per bit to achieve the required QoS and interference on other users of the system, Serve the purpose of balancing the need to maximize battery life. In achieving this, uplink power control only overcomes interference from other users in the same cell and neighboring cells and adapts to the characteristics of the radio propagation channel, including path loss, shadowing, and fast fading Must. The role of power control (PC) has become extremely important in controlling the interference on neighboring cells while providing the necessary SINR (signal to interference and noise ratio). The idea of a classic PC scheme in the uplink is that all users are received with the same SINR, which is known as full compensation. As an alternative, 3GPP uses LTE Rel. For 8/9, we decided to use Fractional Power Control (FPC). This new feature allows users with more severe path loss to operate with lower SINR requirements, thus making them more likely to cause less interference to neighboring cells.

  LTE Rel. The power control scheme provided in 8/9 utilizes a combination of open loop control and closed loop control. One mode of operation involves setting a coarse operating point for the transmit power density spectrum by open loop means based on path loss estimation. Thereafter, faster operation can be applied around the open loop operating point by closed loop power control. This controls interference and fine tunes the power settings to suit channel conditions including fast fading.

  Using this combination of mechanisms, LTE Rel. The power control scheme in 8/9 provides support for operation in two or more modes. It can be viewed as a toolkit for different power control strategies depending on deployment scenarios, system loads, and carrier preferences.

  The detailed power control equation is LTE Rel. For Physical Uplink Shared Channel (PUSCH), Physical Uplink Control Channel (PUCCH), and Sounding Reference Signal (SRS). 8/9 (http://www.3gpp.org, section 5.1 of 3GPP TS36.213, “Physical layer procedures”, version 8.8.0, which is incorporated herein by reference. ). The equations for each of these uplink signals follow the same basic principle, and in any case they are derived from two main terms: static or quasi-static parameters signaled by the eNodeB. The basic open-loop operating point and the dynamic offset updated every subframe can be considered as the sum of the basic open-loop operating point.

The basic open loop operating point for transmit power per resource block depends on several factors including intra-cell interference and cell load. The basic open loop operating point is a quasi-static basic level (semi−) further composed of two components, a common power level for all user equipment in the cell (measured in dBm) and a UE specific offset. (static base level) P ₀ and an open-loop path-loss compensation component. The dynamic offset portion of power per resource block can also be further divided into two components, a component that depends on the MCS, and an explicit transmitter power control (TPC) command.

A component that depends on MCS (referred to as Δ _TF in the LTE specification, where TF means “transport format”) is the transmission data for each resource block, the data of the information to be transmitted -Allows to be adapted according to the rate.

  The other component of the dynamic offset is a UE specific TPC command. These are two different modes: cumulative TPC commands (available for PUSCH, PUCCH, and SRS) and absolute TPC commands (available only for PUSCH) ( Absolute TPC command). For PUSCH, switching between these two modes is configured semi-statically for each UE via RRC signaling—ie, the mode cannot be changed dynamically. When using cumulative TPC commands, each TPC command signals a power step relative to the previous level. Uplink transmitter power control in a mobile communication system minimizes the demand for transmitter energy per bit to achieve the required QoS and interference on other users of the system, and reduces the battery on the user equipment. It serves the purpose of balancing the need to maximize life.

  In achieving this, uplink power control only overcomes interference from other users in the same cell and neighboring cells and adapts to the characteristics of the radio propagation channel, including path loss, shadowing, and fast fading Must.

The setting of the UE transmission power P _PUSCH [dBm] for PUSCH transmission in the reference subframe i is
P _PUSCH (i) = min {P _CMAX , ₁₀ log ₁₀ (M _PUSCH (i)) + P _{O — PUSCH} (j) + α (j) · PL + Δ _TF (i) + f (i)} (Formula 1)
(See 3GPP TS 36.213, section 5.1.1.1).
_-PCMAX is the maximum UE transmit power selected by UEs within a given range (see below).
-M _PUSCH is the number of allocated physical resource blocks (PRBs). The more PRBs are allocated, the more uplink transmission power is allocated.
_{-P0_PUSCH} (j) indicates the base transmit power signaled by the RRC. In the case of semi-persistent scheduling (SPS) and dynamic scheduling, this means that the nominal component P _{O_NOMINAL_PUSCH} (j) ε [−126,. . . , 24] and the component P _{O_UE_PUSCH} (j) ε [−127,. . . , −96]. In the case of RACH message 3, this is an offset from the preamble transmission power.
-Α represents a cell specific parameter (broadcast on system information). This parameter indicates how much the path loss PL is compensated. α = 1 means that the received signal level at the eNodeB is the same regardless of the location of the user equipment, ie, near the cell edge or in the middle. If the path loss is fully compensated, it is avoided that the data rate gets worse the closer to the cell edge. In the case of SPS and dynamic scheduling, α∈ {0, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1}, and in the case of RACH message 3, α ( j) = 1.
-PL is the UE path loss derived at the user equipment based on the measured value of the reference signal received power (RSRP) and the transmitted power of the signaled reference signal (RS). PL is
PL = reference signal power-higher layer filtered RSRP
Can be defined as
Δ _TF is a power offset depending on the modulation and coding scheme (transport format). Therefore, Δ _TF allows to adapt the transmission power per resource block according to the data rate of the transmission information.
F (i) is a function of the closed loop power control command signaled from the eNodeB to the UE. In the case of a cumulative TPC command, f () represents the cumulative amount. Whether the closed-loop command is cumulative (each TPC command signals a power step for the previous level) or absolute (each TCP command is independent of the sequence of previous TPC commands) , Set by higher layers. For cumulative TPC commands, two sets of power step values are provided: (-1, 1) dB for DCI format 3A and (-1, 0 + 1, +3) dB for DCI format 3 Is done. The set of values that can be signaled by an absolute TPC command is (−4, −1,1,4) dB as indicated by DCI format 3.

Power Headroom Report In order to assist the eNodeB in scheduling uplink transmission resources for different user equipment in an appropriate manner, it is important that the user equipment can report available power headroom to the eNodeB. is there.

  The eNodeB may use the power headroom report to determine how much uplink bandwidth is available for the user equipment per subframe. This helps to avoid allocating uplink transmission resources to user equipment that cannot use it to avoid wasting resources.

  The power headroom report ranges from +40 to −23 dB (available at http://www.3gpp.org, which is incorporated herein by reference in its entirety, 3GPP TS36.133, “Requirements for support of radio resource management ", version 8.7.0, section 9.1.8.4). The negative part of the range allows the user equipment to signal to the eNodeB how much the UE has received a UL grant that requires more transmit power than is available to the UE. This allows the eNodeB to reduce the size of subsequent grants, thus releasing transmission resources allocated to other UEs.

  The power headroom report can only be transmitted in a subframe in which the UE has a UL transmission grant. The report relates to the subframe in which it is transmitted. Thus, the headroom report is a predicted value, not a direct measurement, and the UE cannot directly measure the actual transmit power headroom of the subframe in which the report is transmitted. It therefore relies on a reasonably accurate calibration of the UE power amplifier output.

A number of criteria are defined that trigger power headroom reports. They include the following:
-Significant changes in estimated path loss since the last power headroom report.
-A time longer than the set time has elapsed since the last power headroom report.
-More closed-loop TPC commands than the set number were executed by the UE.

  The eNodeB can set parameters for controlling each of these triggers according to system load and scheduling algorithm requirements. More specifically, RRC sets dl-PathlossChange to set the change in measured downlink path loss that triggers the power headroom report by setting two timers periodicPHR-Timer and prohibitPHR-Timer. Control power headroom reporting by signaling.

  The power headroom report is sent as a MAC control element. The power headroom report consists of a single octet, the upper 2 bits are reserved, and the lower 6 bits represent the 64 dB values of the 1 dB step described above. The structure of the MAC control element is shown in FIG.

The effective UE power headroom PH [dB] for subframe i is
PH (i) = P _CMAX − {10 · log ₁₀ (M _PUSCH (i)) + P _{0 — PUSCH} (j) + α (j) · PL + Δ _TF (i) + f (i)} (Formula 2)
(See section 5.1.1.2 of 3GPP TS 36.213).

The power headroom is rounded to the nearest value within the range [40; -23] dB of 1 dB steps. P _CMAX is the maximum total UE transmit power (or maximum total transmit power of the user equipment), based on the following _constraints at a value selected by the user equipment from within a given range from _{P CMAX_L} to _{P CMAX_H} is there.
− P _{CMAX_L} ≦ P _CMAX ≦ P _{CMAX_H}
-P _{CMAX_L} = min (P _EMAX -ΔT _C , P _PowerClass -MPR-AMPR-ΔT _C )
_{- P CMAX_H = min (P EMAX} , P PowerClass)

P _EMAX is a value signaled by the network and ΔT _C , MPR, and AMPR (A-MPR (also referred to as Additional Maximum Power Reduction)) is http: // www. 3 gpp. 3GPP TS 36.101, “Evolved Universal Terrestrial Access (E-UTRA); User Equipment (UE) radio transmission and version 8”, which is available at www.org.org and is incorporated herein by reference. , As defined in section 6.2.

  MPR is a power reduction value, the so-called maximum power reduction, used to control Adjacent Channel Leakage Power Ratio (ACLR) associated with various modulation schemes and transmission bandwidths. The adjacent channel can be, for example, another evolved universal terrestrial radio access (E-UTRA) channel or a UTRA channel. Maximum allowed power reduction (MPR) is also defined in 3GPP TS 36.101. It depends on the channel bandwidth and the modulation scheme. The reduction in user equipment can be less than this maximum allowable power reduction (MPR) value. 3GPP defines an MPR test that verifies that the maximum transmit power of the user equipment is equal to or greater than the nominal maximum total transmit power minus MPR while still complying with ACLR requirements.

Table 1 below shows the maximum power reduction for UE power class 3.

  For example, when allocating 10 MHz channel bandwidth, when using QPSK modulation to allocate more than 12 resource blocks, the MPR applied by the user equipment should be 1 dB or less. The actual MPR applied by the user equipment depends on the UE implementation and is therefore unknown to the eNB.

As pointed out above, AMPR is an additional maximum power reduction. AMPR is band specific and is applied when configured by the network. As can be seen from the above description, _PCMAX is specific to the UE implementation and is therefore unknown to the eNodeB.

であることに留意されたい。 FIG. 41 illustrates an example scenario for UE transmit power status and corresponding power headroom. On the left side of FIG. 41, the user equipment is not power limited (positive PHR), but on the right side of FIG. 41, the negative power headroom implies the power limit of the user equipment. P _{CMAX_L} ≦ P _CMAX ≦ min (P _EMAX , P _PowerClass ), where the lower boundary P _{CMAX_L} generally depends mainly on the maximum power reduction MPR and the additional maximum power reduction AMPR, ie

Please note that.

Uplink Power Control for Carrier Aggregation One key point of LTE-Advanced UL power control is that UL power control specific to component carriers is supported, i.e. each configured for the UE. There will be one independent power control loop for the UL component carrier. In addition, power headroom is reported for each component carrier.

In Rel-10, within the range of carrier aggregation, there are two maximum power limits, a maximum total UE transmit power and a CC-specific maximum transmit power. RAN1 agreed that at the RAN1 # 60bis meeting, the power headroom report reported for each CC would take into account maximum power reduction (MPR). In other words, the power reduction applied to the UE is taken into account by the CC-specific maximum transmission power P _{CMAX, c} (where c represents the component carrier).

  Unlike Rel-8 / 9, for LTE-A, the UE requires a larger MPR value compared to Rel-8 / 9 and also results in simultaneous transmission of PUSCH-PUCCH resulting in greater variation in the applied MPR value. Multi-cluster scheduling and simultaneous transmission on multiple CCs must also be handled.

Since the actual power reduction depends on the type of allocation, the standardized MPR value, and also the UE implementation, the eNB has no knowledge of the power reduction applied by the UE for each CC. Please keep in mind. Thus, the eNB does not know the maximum transmit power specific to the CC for which the UE calculates the PHR. In Rel-8 / 9, for example, the maximum transmission power Pcmax of the UE may be within some specific range as described below.
P _{CMAX_L} ≦ P _CMAX ≦ P _{CMAX_H}

  Due to the fact that the power reduction applied by the UE with respect to the CC's maximum transmit power is not known by the eNB, in Rel-10 an extended power headroom MAC control element. It was agreed to introduce a new power headroom MAC control element, also called. The main difference from the Rel-8 / 9 PHR MAC CE format is that the new power headroom MAC control element includes a Rel-8 / 9 power headroom value for each activated UL CC, Therefore, it is a variable size. In addition, the new power headroom MAC control element reports not only the power headroom value for the CC, but also the corresponding Pcmax, c (maximum transmit power for CC with index c) value. In order to consider the simultaneous transmission of PUSCH-PUCCH, the UE reports the Rel-8 / 9 power headroom value (referred to as Type 1 power headroom) related to the PUSCH-only transmission for the P cell, and the UE If configured for simultaneous transmission of PUSCH-PUCCH, it reports further power headroom values that take into account the transmission of PUCCH and PUSCH, also referred to as Type 2 power headroom (see FIG. 21). Further details of the extended power headroom MAC control element can be found in section 6.1.3.6a of TS 36.321.

を超えそうな場合、ＵＥは、ＰＵＳＣＨ／ＰＵＣＣＨ上のアップリンクの送信電力を引き下げる必要がある。定義された電力のスケーリング中のアップリンク・チャネルの優先順位付けのための特定の規則が存在する。基本的に、ＰＵＣＣＨ上で送信される制御情報が最も高い優先順位を有し、すなわち、ＰＵＳＣＨの送信は、ＰＵＣＣＨの送信電力が低減される前に最初に引き下げられる。これは、満足される必要がある以下の条件によってやはり表され得る。

ここで、

は、Ｐ_{ＰＵＣＣＨ}（ｉ）（サブフレームｉにおけるＰＵＣＣＨの送信電力）のリニア値（ｌｉｎｅａｒ ｖａｌｕｅ）であり、

は、Ｐ_{ＰＵＳＣＨ，ｃ}（ｉ）（サブフレームｉにおけるキャリアｃ上のＰＵＳＣＨの送信電力）のリニア値であり、

は、サブフレームｉにおけるＵＥの合計の構成された最大出力電力Ｐ_ＣＭＡＸのリニア値であり、ｗ（ｉ）は、サービング・セルｃに関する

の倍率であり、０≦ｗ（ｉ）≦１である。サブフレームｉにおいてＰＵＣＣＨの送信がない場合は、

である。 UE total transmit power, that is, UE transmit power with maximum sum of transmit power on all CCs

UE is required to reduce the uplink transmit power on PUSCH / PUCCH. There are specific rules for prioritization of uplink channels during defined power scaling. Basically, the control information transmitted on the PUCCH has the highest priority, i.e. the transmission of the PUSCH is pulled down first before the transmission power of the PUCCH is reduced. This can also be represented by the following conditions that need to be satisfied.

here,

Is a linear value of P _PUCCH (i) (transmission power of PUCCH in subframe i),

Is a linear value of P _{PUSCH, c} (i) (transmission power of PUSCH on carrier c in subframe i),

Is the linear value of the total configured maximum output power P _CMAX of the UE in subframe i, and w (i) is related to serving cell c

And 0 ≦ w (i) ≦ 1. If there is no PUCCH transmission in subframe i,

It is.

を超えそうである場合に関して、ＵＥは、条件

が満足されるように、サブフレームｉにおけるＵＣＩをともなわないサービング・セルに関する

をスケーリングし、ここで、

は、ＵＣＩをともなうセルに関するＰＵＳＣＨの送信電力であり、ｗ（ｉ）は、ＵＣＩをともなわないサービング・セルｃに関する

の倍率である。この場合、

であり、ＵＥの総送信電力がまだ

を超えそうでない限り、電力のスケーリングは

に適用されない。ｗ（ｉ）の値は、ｗ（ｉ）＞０であるときはサービング・セルによらず同じであるが、特定のサービング・セルに関して、ｗ（ｉ）は０である可能性があることに留意されたい。 The UE has a PUSCH transmission with uplink control information (UCI) on serving cell j and a PUSCH without UCI in any of the remaining serving cells, and the total transmit power of the UE is

For cases where it is likely to exceed

For the serving cell without UCI in subframe i

Scale, where

Is the transmission power of the PUSCH for a cell with UCI, and w (i) is for the serving cell c without UCI

Is the magnification. in this case,

And the total transmit power of the UE is still

Unless it is likely to exceed, power scaling is

Not applicable. The value of w (i) is the same regardless of the serving cell when w (i)> 0, but for a particular serving cell, w (i) may be 0. Please keep in mind.

を超えそうである場合、ＵＥは、

および

にしたがって

を得る。 The UE has a simultaneous transmission of PUCCH and PUSCH with UCI on serving cell j and a transmission of PUSCH without UCI in any of the remaining serving cells, and the total transmit power of the UE is

UE is likely to exceed

and

According to

Get.

Timing Advance For 3GPP LTE uplink transmission scheme, single carrier frequency division multiple access (SC-FDMA) is selected to achieve orthogonal multiple access in time and frequency between different user equipments transmitting on the uplink It was.

  Uplink orthogonality is maintained by ensuring that transmissions from different user equipment in the cell are time aligned at the eNodeB receiver. This prevents intra-cell interference from occurring between user equipment allocated to transmit in consecutive subframes and between user equipment transmitting on adjacent subcarriers. Uplink transmission time alignment applies timing advance at the user equipment transmitter relative to the received downlink timing, as illustrated in FIG. It is realized by. Its main role is to counteract different propagation delays between different user equipments.

  FIG. 9a illustrates the misalignment of uplink transmissions from two mobile stations when uplink timing alignment is not performed, such as eNodeB receiving respective uplink transmissions from two mobile stations at different timings. Show.

  FIG. 9b, in contrast, shows uplink transmissions synchronized between the two mobile stations. Uplink timing alignment is performed by each mobile station and is applied to the uplink transmission so that the uplink transmissions from the two mobile stations arrive at the eNodeB at substantially the same timing.

Initial Timing Advance Procedure When the user equipment is synchronized to the downlink transmission received from the eNodeB, the initial timing advance is set by a random access procedure as described below. The user equipment transmits a random access preamble, and the eNodeB can estimate the uplink timing based on the random access preamble. The eNodeB responds with an 11-bit initial timing advance command included in the random access response (RAR) message. This allows the timing advance to be configured by the eNodeB from 0 to a maximum of 0.67 ms with a granularity of 0.52 μs.

  For more information on 3GPP LTE (Release 8/9) uplink timing and timing advance control, see Stefania Sesia, Issam Toufik, and Matthew Baker, “LTE-The UMTS Long Term Evolution,” which is incorporated herein by reference. : From Theory to Practice ", John Wiley & Sons, Ltd. 2009, Chapter 20.2.

Timing Advance Update When timing advance is initially set for each user equipment, the timing advance is updated from time to time to negate the change in uplink signal arrival time at the eNodeB. In deriving the timing advance update command, the eNodeB can measure any useful uplink signal. Details of the uplink timing measurement at the eNodeB are not defined and are left to the eNodeB implementation.

  The timing advance update command is generated at the eNodeB's medium access control (MAC) layer and sent to the user equipment as a MAC control element that can be multiplexed with data on the physical downlink shared channel (PDSCH). Similar to the initial timing advance command according to the random access channel (RACH) preamble, the update command has a granularity of 0.52 μs. The range of the update command is ± 16 μs, allowing a step change in the uplink timing equal to the length of the extended cyclic prefix. In general, these update commands are sent less frequently than about every 2 seconds. In fact, even for user equipment moving at 500 km / h, the change in the length of the round trip path corresponding to a change in the round trip time of 0.93 μs / s is 278 m / s or less, so a fast update is required. It is unlikely.

  The eNodeB balances the overhead of sending periodic timing update commands to all UEs in the cell against the UE's ability to transmit quickly when data arrives in the UE's transmission buffer. Thus, the eNodeB configures a timer for each user equipment that the user equipment restarts whenever a timing advance update is received. If the user equipment does not receive another timing advance update before the timer expires, the user equipment must consider that it has lost uplink synchronization (available at http://www.3gpp.org) See also 3GPP TS 36.321, “Evolved Universal Terrestrial Radio Access (E-UTRA); Medium Access Control (MAC) protocol specification”, version 8.9, incorporated herein by reference. Wanna)

  In such cases, in order to avoid the risk of causing interference to uplink transmissions from other user equipment, the UE is not allowed to make any kind of other uplink transmissions and recovers uplink timing. In order to do this, it is necessary to return to the initial timing alignment procedure.

When receiving the timing advance command, the user equipment adjusts the uplink transmission timing of the user equipment regarding the PUCCH / PUSCH / SRS of the primary cell. Timing advance command indicates a change in the timing of the relative uplink to the timing of the current uplink as a multiple of 16T _s.

Random Access Procedure An LTE mobile terminal may be scheduled for uplink transmission only if its uplink transmission is time synchronized. Thus, the random access (RACH) procedure plays an important role as an interface between an unsynchronized mobile terminal (UE) and orthogonal transmission of uplink radio access.

Basically, LTE random access is used to perform uplink time synchronization for user equipment that has either not yet synchronized or lost user equipment uplink. Once the user equipment has uplink synchronized once, the eNodeB can schedule uplink transmission resources for that user equipment. Thus, the following scenario applies to random access.
-User equipment that is in RRC_CONNECTED state but not in uplink synchronization wants to send new uplink data or control information-User equipment in RRC_CONNECTED state but not in uplink synchronization Are required to receive downlink data and are therefore required to transmit corresponding HARQ feedback, ie ACK / NACK, on the uplink. This scenario is also referred to as downlink data arrival-a user equipment in the RRC_CONNECTED state is handed over from its current serving cell to a new handover destination cell and uplink time synchronization is performed in the handover destination cell. A random access procedure is performed--for example, transition from RRC_IDLE state to RRC_CONNECTED for initial access or tracking area update-recovery from radio link failure, i.e. re-establishing RRC connection

  There is another further case where the user equipment performs a random access procedure even though the user equipment is time synchronized. In this scenario, if the user equipment does not have any other uplink resources assigned to send the scheduling request, i.e. no dedicated scheduling request (D-SR) channel is configured, the user equipment Uses a random access procedure to send a scheduling request, ie, an uplink buffer status report, to its eNodeB.

  LTE has two types that allow access to be contention-based, i.e. with either inherent risk of collision or contention-free (non-contention-based). Provide random access procedures. Contention-based random access can be applied to all six scenarios listed above, while non-contention-based random access procedures are used for downlink data arrival and handover scenarios. Note that only can be applied.

  In the following, the contention based random access procedure is described in more detail in connection with FIG. A detailed description of the random access procedure can also be found in 3GPP 36.321, section 5.1.

  FIG. 7 shows an LTE contention-based RACH procedure. This procedure consists of four “steps”. Initially, the user equipment transmits a random access preamble to the eNodeB on a physical random access channel (PRACH) (701). The preamble is selected by the user equipment from the set of available random access preambles reserved by the eNodeB for contention based access. In LTE, there are 64 preambles per cell that can be used for contention free and contention based random access. The set of contention-based preambles can be further subdivided into two groups. Thus, the preamble selection can carry 1-bit information indicating information on the amount of transmission resources required for the first scheduled transmission called msg3 in TS36.321 (see step 703). The system information broadcast in the cell includes information on which signature (preamble) exists in each of the two subgroups and the meaning of each subgroup. The user equipment randomly selects one preamble from the subgroup corresponding to the size of the transmission resource required for transmission of message 3.

  After the eNodeB detects the RACH preamble, the eNodeB identifies the time-frequency slot in which the preamble was detected (random access) PDSCH (physical downlink shared channel) addressed on the PDCCH using RA-RNTI A random access response (RAR) message is transmitted (702). When multiple user equipments, also called collisions, transmit the same RACH preamble on the same PRACH resource, they receive the same random access response.

  The RAR message is for the transmission of the detected RACH preamble, the timing alignment command (TA command) to synchronize the subsequent uplink transmission, and the first scheduled transmission (see step 703). It carries initial uplink resource allocation (granting) and Temporary Cell Radio Network Temporary Identifier (T-CRNTI) allocation. This T-CRNTI is not yet known to the eNodeB at this point in time because the “real” identity of the mobile device is known to the mobile (s) in which the RACH preamble (s) were detected until the RACH procedure is terminated. Used by eNodeB to address devices.

  Furthermore, the RAR message may also include a so-called back-off indicator that the eNodeB can set to instruct the user equipment to wait for a period of time before trying the random access attempt again. The user equipment monitors the PDCCH for receipt of a random access response within a given time window configured by the eNodeB. If the user equipment does not receive a random access response within the configured time window, the user equipment retransmits the preamble on the next PRACH opportunity, taking into account the potential backoff period.

  In response to the RAR message received from the eNodeB, the user equipment sends an initial scheduled uplink transmission on the resources allocated by the grant in the random access response (703). This scheduled uplink transmission carries a message of an actual random access procedure such as, for example, an RRC connection request, a tracking area update, or a buffer status report. In addition, this scheduled uplink transmission includes either the C-RNTI for user equipment in RRC_CONNECTED mode or a unique 48-bit user equipment identification when the user equipment is in RRC_IDLE mode. . If a preamble collision occurs in step 701, ie, multiple user equipments transmit the same preamble on the same PRACH resource, the colliding user equipments receive the same T-CRNTI in a random access response. That is, when transmitting the scheduled transmissions of those user equipments (703), they will also collide on the same uplink resources. This can lead to interference from which the transmissions from the colliding user equipment are not decoded at the eNodeB, and the user equipments will be randomized after reaching the maximum number of retransmissions for their scheduled transmissions. The access procedure will start again. If a scheduled transmission from one user equipment is successfully decoded by the eNodeB, the contention remains unresolved with respect to the other user equipment.

  For resolution of this type of conflict, the eNodeB sends a conflict resolution message addressed to the C-RNTI or temporary C-RNTI (704), in the latter case included in the scheduled transmission of step 703. 48-bit user device identification information is returned as it is. The contention resolution message supports HARQ. If the message sent in step 703 is successfully decoded after the collision, the HARQ feedback (ACK) detects the user's identity, either C-RNTI or unique user equipment ID. Sent only by the device. The other UEs understand that there was a collision in step 1 and can immediately stop the current RACH procedure and start another RACH procedure.

  FIG. 8 shows 3GPP LTE Rel. 8/9 shows a contention-free random access procedure. Compared to contention-based random access procedures, contention-free random access procedures are simplified. The eNodeB provides the user equipment with a preamble to use for random access (801), so there is no risk of collision, i.e., there are no multiple user equipments transmitting the same preamble. Accordingly, the user equipment transmits the preamble signaled by the eNodeB on the PRACH resource in the uplink (802). For contention-free random access, there is no need for contention resolution since multiple UEs can avoid sending the same preamble, which in turn is based on the contention-based approach shown in FIG. It suggests that step 704 of the procedure may be omitted. Basically, the contention-free random access procedure is terminated after successfully receiving the random access response.

  When carrier aggregation is configured, the first three steps of the contention-based random access procedure are performed in the P cell, but contention resolution (step 704) may be cross-scheduled by the P cell. There is.

  The initial preamble transmit power setting is based on open-loop estimation with full path loss compensation. This is designed to ensure that the received power of the preamble is independent of path loss.

  The eNB configures additional power offsets depending on, for example, the desired received SINR, the level of uplink interference and noise measured in the time-frequency slot assigned to the RACH preamble, and possibly the preamble format There is also a possibility to do. In addition, the eNB configures power ramping of the preamble for each retransmitted preamble, i.e., if the PRACH transmission attempt is unsuccessful, the transmission is raised by a fixed stage. there is a possibility.

The power of PRACH is
PPRACH = min {P _{CMAX, c} (i), PREAMBLE_RECEIVED_TARGET_POWER + PL _C } [dBm]
It is determined by the UE by evaluating _{where, P CMAX,} c (i) is the largest UE transmit power that is configured for subframe i of the primary cell, PL _C is UE regarding primary cells Is an estimate of the downlink path loss calculated in

PREAMBLE_RECEIVED_TARGET_POWER is
preambleInitialReceivedTargetPower + DELTA_PREAMBLE + (PREAMBLE_TRANSMISION_COUNTER-1) * powerRampingStep
Set to

Channel Quality Feedback Elements 3GPP LTE has the following three basic elements that may or may not be provided as feedback on channel quality.
-Modulation and coding scheme indicator (MCSI), also called channel quality indicator (CQI) in the 3GPP LTE specification.
-Precoding matrix indicator (PMI)
-Rank indicator (RI)

  MCSI proposes the modulation and coding scheme to be utilized for downlink transmission to reporting user equipment, while PMI uses the assumed transmission matrix rank or the transmission matrix rank given by RI. Indicates a precoding matrix / vector used for multi-antenna transmission (MIMO). Details on channel quality reporting and transmission mechanisms can be found in 3GPP TS 36.212, “Evolved Universal Terrestrial Radio Access (E-UTRA); Multiplexing and channel coding (Release 8)”, Version 8.7.0, Section 5.2. And 3GPP TS 36.213, “Evolved Universal Terrestrial Radio Access (E-UTRA); Physical layer procedures (Release 8)”, Version 8.7.0, Section 7.2 (both references are ht, Available at: //www.3gpp.org, by reference Which is incorporated herein).

  All of these elements are collectively referred to herein as channel quality feedback. Thus, the channel quality feedback can include any combination of multiple MCSI, PMI, and RI values. The channel quality feedback report can further include or consist of metrics such as channel covariance matrix or elements, channel coefficients, or other suitable metrics that will be apparent to those skilled in the art.

Channel quality feedback in LTE-A (Release 10) Since only one component carrier is defined in LTE (Release 8), ambiguity as to which part of the system bandwidth CQI reporting takes place in the user equipment not exist. The CQI request flag (along with the current transmission mode) indicates to the user equipment unambiguous how CQI feedback should be provided to the eNodeB.

  With the introduction of carrier aggregation in LTE-A (Release 10), assuming that the LTE (Release 8) CQI reporting procedure should be reused, how the user equipment can interpret CQI requests can differ Sex exists. As shown in FIG. 38, generally, UL-DCI (including CQI request) for uplink transmission transmitted from the eNodeB or relay node to the user equipment is in a single downlink component carrier. It can be assumed that they are arranged. A simple rule for handling CQI requests at the user equipment is that whenever the UL-DCI requests a CQI transmission by the user equipment, the request is sent to the downlink component carrier on which the corresponding UL-DCI was sent. It is something that applies to. That is, the user equipment only transmits aperiodic CQI feedback for the downlink component carrier that simultaneously included UL-DCI requesting a CQI report in a given UL transmission.

  An alternative processing of UL-DCI that includes a CQI request is shown in FIG. Whenever UL-DCI requests a CQI transmission by the user equipment, the user equipment applies the request to all downlink component carriers available for downlink transmission to the user equipment.

  If downlink transmission can be performed on multiple component carriers, efficient scheduling and link adaptation depends on availability of accurate and up-to-date CQI. However, in order to efficiently use control signaling and CQI transmission resources, it controls how many and which component carriers are requested (from the network side) and transmitted (from the terminal side). It must be possible to do.

  According to the first solution described above with respect to FIG. 39, in order to request CQI for multiple component carriers, the number of component carriers for which CQI is required and the UL- The number of DCI messages is the same. In other words, requesting CQI for 5 component carriers requires sending 5 times more UL-DCI messages than requesting CQI for just one component carrier. Therefore, this solution is not very efficient from the perspective of downlink control overhead. According to the above second solution shown in FIG. 39, a single uplink DCI message requests CQI for all component carriers. Therefore, the downlink control overhead is very small. However, the resulting uplink transmission will result in CQIs for all component carriers even if the network knows that it currently only requires CQIs for the selected component carrier. Always request a large amount of resources to enable sending This solution is therefore not efficient for the use of uplink resources and does not provide any flexibility for the number of component carrier CQIs required.

Timing Advance and Component Carrier Aggregation in the Uplink In the current specification of the 3GPP standard, user equipment has only one timing advance value and the uplinks on all aggregated component carriers Apply this to the transmission. Currently, aggregation of cells within the same frequency band, so-called intra-frequency carrier aggregation is supported. In particular, uplink timing synchronization is performed on the P cell, eg, by a RACH procedure on the P cell, and then the user equipment can use the same uplink timing for uplink transmission on the aggregated S cell. Is used. A single timing advance for all aggregated uplink component carriers is described in 3GPP LTE-A Rel. Up to 10 current specifications are considered sufficient because they only support carrier aggregation of carriers from the same frequency band.

  However, in the future, e.g. in future release 11, there is a possibility of aggregating uplink component carriers from different frequency bands, in which case those uplink component carriers may have different interference and coverage. May be exposed to the characteristics of Given uplink component carriers on remote frequency bands, uplink transmissions using those uplink component carriers can be subject to the effects of different transmission channels. In other words, because the transmission channel needs to be assumed to be frequency selective, uplink component carriers on distant frequency bands have different effects due to scattering, multipath propagation, and channel fading. May be given. Therefore, aggregation of uplink component carriers from different frequency bands must compensate for different propagation delays in those frequency bands.

  Furthermore, an arrangement of technologies such as a remote radio head (RRH) as shown in FIG. 13 or a frequency selective repeater (FSR) as shown in FIG. Further causes different interference and propagation scenarios. For example, FIG. 14 shows how the FSR relays only the signal at frequency f2 for component carrier 2 (CoCa2), and the signal at frequency f1 is not enhanced by the FSR. As a result, assuming that the signal strength of the signal from the FSR is higher than the signal strength of the eNodeB (not shown), the component carrier 2 is received by the user equipment via the frequency selective repeater, The UE receives component carrier 1 (CoCa1) directly from the eNodeB. This leads to different propagation delays between the two component carriers.

  Thus, it is necessary to introduce more than one timing advance within one user equipment, ie a separate timing advance may be required for a particular component carrier (serving cell) There is.

  One obvious solution is to perform the RACH procedure on each of the S cells as well as the P cell to achieve uplink synchronization. However, performing the RACH procedure in the S cell has various disadvantages.

  As a direct result, the user equipment is required to implement the protocol part of the random access procedure for the aggregated SCell, which is not only in the RRC layer, but also in the physical layer, the MAC layer. Will also affect the UE complexity.

  When considering the simultaneous transmission of PRACH and PUSCH / PUCCH in one subframe, ie TTI, the power control / power allocation procedure is complex. This is because the uplink of the user equipment is out of sync on one component carrier, eg S cell, while the uplink remains on another uplink component carrier, eg P cell. May be the case. In order to re-synchronize the uplink for the S cell, the user equipment performs RACH access, eg, commanded by PDCCH. As a result, the user equipment transmits a RACH preamble, i.e., performs PRACH transmission, and in the same TTI, the user equipment also transmits PUSCH and / or PUCCH.

  Currently, the power control loop for PUSCH / PUCCH and PRACH is completely independent, ie, PRACH power is not considered when determining PUSCH / PUCCH power, and vice versa. To cope with simultaneous transmission of PRACH and PUSCH / PUCCH, changes to the uplink power control algorithm are required. For example, at present, only PUCCH, PUSCH with multiplexed uplink control information (UCI), and PUSCH without UCI are considered for limiting power, so power limitation due to power limitation. It is necessary to consider the transmission of PRACH when scaling needs to be used. The PUCCH is given the highest priority over the PUSCH, and the PUSCH with multiplexed UCI is considered to have a higher priority than the PUSCH without UCI.

PUSCH with PUCCH>UCI> PUSCH with no UCI
The prioritization rules for limiting power that are listed in the chapter on uplink power control need to be extended by the transmission of PRACH. However, on the one hand, uplink control information transmitted on PUCCH or PUSCH has high priority to allow proper system operation, and on the other hand, PRACH also minimizes the delay incurred by RACH procedure. There is no easy and simple solution in this respect, since it should still be prioritized to ensure a high probability of detection at the eNB.

  In addition to the power control perspective, there is a further penalty for power amplifiers that need to handle simultaneous transmission of PRACH and PUSCH / PUCCH. There is a specific difference in uplink timing between PRACH and PUSCH / PUCCH, for example, the timing advance for PRACH is naturally 0, and the guard time, GT, is in the range of 96.88 μs to 715.63 μs. is there. This is shown in FIG. 22, which shows the transmission of PUSCH on component carrier 0 and the corresponding PRACH transmission on component carrier 1. As is apparent, PRACH transmission is not time aligned with PUSCH transmission for subframes.

  Due to the guard time, there is an undesirable power fluctuation within one subframe. These power transients further complicate the user equipment implementation, in other words, the maximum power reduction still needs to change in one subframe to meet the EMC requirements.

  With the deployment of technologies such as remote radio head (RRH) or frequency selective repeater (FSR), different propagation paths may introduce different propagation delays in the communication between the eNodeB and the user equipment UE. is there. Assuming different frequency band cell aggregation, as described with respect to FIGS. 13 and 14, the transmission to and / or reception from the eNodeB by the user equipment is due to different propagation delays due to different locations of the eNodeB. As well as RRH or FSR and / or frequency selective channel effects.

  Specifically, different propagation delays and / or frequency selective channel effects not only adversely affect uplink transmissions to the eNodeB via multiple uplink serving cells, but as will become apparent below, It is also inconvenient for downlink transmission to the equipment UE.

  FIG. 37 shows a scenario involving eNodeB, RRH, and user equipment UE.

  As described above, the UE may be able to aggregate downlink serving cells (component carriers) belonging to different or the same frequency band. When the user equipment aggregates the first downlink serving cell provided by the RRH and the second downlink serving cell provided by the eNodeB, the user equipment experiences different propagation delays. Receive downlink transmission from the RRH and downlink transmission from the eNodeB.

  In other words, the user equipment has delayed the serving cell downlink subframe provided by the eNodeB later than the reception of the corresponding downlink subframe of the downlink serving cell provided by the RRH. Received, where the corresponding downlink subframe term refers to subframes having the same subframe number. FIG. 37 also shows different propagation delays.

が小さいとしても、ｅＮｏｄｅＢおよびＲＲＨのダウンリンク・サービング・セルは、それらの異なるロケーションおよび／または周波数選択チャネル効果に起因する、異なる伝搬遅延をこうむる。 In particular, assuming that the serving cell downlink subframe transmission time provided by the eNodeB is time t ₀ , the user equipment receives this downlink subframe at time t _eNodeB . Further, when the corresponding downlink subframe is transmitted synchronously by the eNodeB and the RRH, the transmission time of the corresponding downlink subframe of the serving cell provided by the RRH is also the time t ₀ , and the user The device receives this downlink subframe at time t _RRH . Propagation delay difference between eNodeB and RRH

Even though the eNodeB and RRH downlink serving cells will suffer different propagation delays due to their different location and / or frequency selective channel effects.

  Due to the different propagation delays for downlink transmissions on the serving cell provided by the eNodeB and RRH, the user equipment receives corresponding downlink subframes of different serving cells at different times. Similarly, a frequency selective router (FSR) may also introduce different propagation delays for the user equipment, i.e., in that case, the user equipment is partially downlinked from the FSR and partially from the eNodeB. • Aggregate serving cells.

  For example, in the scenario shown in FIG. 37, the user equipment is located at a distance of 100 km from the eNodeB. If the distance is 100 km, the reception of the downlink subframe from the eNodeB will be 0.33 ms after the transmission time, while the RRH is closer, so the user equipment will be in the serving cell from the RRH. A corresponding downlink subframe is received at an earlier time.

  Different propagation delays are inconvenient for reception operations performed by the user equipment, since the corresponding downlink subframes need to be processed simultaneously by the user equipment. In particular, the corresponding downlink subframe may contain interrelated information such that the user equipment can only process it when it receives the corresponding subframe from all aggregated serving cells. is there.

  An obvious solution is to define that the user equipment includes a receive buffer for temporarily storing data about the component carriers of each serving cell during the time difference between the aggregated serving cells. For example, in the example given above, the delayed data from the eNodeB needs to be buffered by the user equipment. However, providing a large receive buffer causes various disadvantages.

  First, realizing a user equipment having a reception buffer does not solve the problem of delay in downlink transmission processing. In particular, since the corresponding subframes of the aggregated serving cell need to be processed together by the user equipment, one latest reception time of the plurality of corresponding subframes is the plurality of corresponding subframes. As a result, all downlink transmissions of the aggregated serving cell experience the same delay.

  Furthermore, providing a large reception buffer increases the cost of the user equipment and is also inconvenient for the implementation complexity of the user equipment. For example, when the radius is 100 km at the maximum, the required reception buffer size is very large.

  In addition, the corresponding downlink subframes on the aggregated serving cell must be identified in the receive buffer before the user equipment processes them together for decoding, so the user equipment The reception operation performed by this increases the complexity of the user equipment related to the hardware. In the case of a small receive buffer containing only the corresponding subframe of the aggregated serving cell, the user equipment is not required to additionally perform identification of the corresponding downlink subframe.

TS36.212 section 5.3.3 TS36.213 section 8.6 TS36.213 section 7.1.7 3GPP TS 36.211, “Evolved Universal Terrestrial Radio Access (E-UTRA); Physical Channels and Modulation (Release 8)”, Version 8.9.0 or 9.0.0, Section 6.2. 3GPP TS 36.321, “Medium Access Control (MAC) protocol specification”, version 8.7.0, sections 4.2, 4.3, 5.4.3, 6 3GPP TS 36.213, “Physical layer procedures”, version 8.8.0, section 5.1 3GPP TS 36.133, “Requirements for support of radio resource management”, version 8.7.0, section 9.1.8.4. 3GPP TS 36.101, “Evolved Universal Terrestrial Radio Access (E-UTRA); User equipment (UE) radio transmission and reception”, section 8.7.0. 3GPP TS 36.212, “Evolved Universal Terrestrial Radio Access (E-UTRA); Multiplexing and channel coding (Release 8)”, Version 8.7.0, Section 5.2. 3GPP TS 36.213, “Evolved Universal Terrestrial Radio Access (E-UTRA); Physical layer procedures (Release 8)”, Version 8.7.0, Section 7.2. www. cpri. info TS36.133 section 7.1.2

  The present invention seeks to avoid the various disadvantages described above.

  One object of the present invention is to provide a mechanism for aligning the timing of uplink transmissions on those uplink component carriers when different propagation delays are imposed on the transmissions on the uplink component carriers. It is to propose. Another object of the present invention is to propose a mechanism for enabling a mobile terminal to perform time alignment of uplink component carriers without performing a random access procedure. A further object of the present invention is that the mobile terminal aggregates various downlink component carriers (serving cells) without requiring unnecessarily high user equipment receiver requirements, eg, large UE reception windows. It is to propose a mechanism that makes this possible.

  This object is solved by the subject matter of the independent claims. Advantageous embodiments are defined by the dependent claims. A further object is to propose a handover mechanism that makes it possible to reduce handover delays by time alignment of multiple uplink component carriers.

  According to a first aspect of the invention, a mobile terminal is already in time as a target cell, for a reference uplink cell controlled by the same or different aggregation access point. The timing information based on the procedure for aligning the time of uplink cells (hereinafter referred to as target cells) that are relatively unaligned, and aligning the times of uplink target cells that are not aligned in time. Send to point. It is assumed that at least one existing cell is already in time and serves as a reference cell for the time alignment procedure of the present invention. Advantageously, timing information transmitted to the aggregation access point may be used by the aggregation access point to control the time alignment process in the uplink target cell.

  More specifically, instead of performing a random access channel, RACH, procedure, the mobile terminal can measure the up-time on the uplink target cell in time by measuring specific timing difference information. Align link transmission times. The specific timing difference information enables the mobile terminal to estimate a time alignment to align the mobile terminal uplink transmission time on the uplink target cell.

  At that time, the mobile terminal calculates information regarding the necessary uplink timing alignment to be used by the mobile terminal to align the time of the target cell with respect to the reference cell already in time. In order to calculate the timing advance, the mobile terminal uses at least the measured value and the timing advance of the reference cell.

  Subsequently, the mobile terminal uses the calculated information to update the mobile terminal on the uplink of the target cell relative to the timing advance value of the reference cell (a value known to the mobile terminal). Adjust the transmission timing of the link.

  The specific timing difference information may also be used by the aggregation access point to estimate the time alignment for mobile terminal uplink transmissions on the uplink target cell. In particular, the timing advance of uplink transmission by the mobile terminal on the reference cell, which is used as a reference for aligning the time of the uplink target cell, is already known by the aggregation access point. Thus, the aggregation access point can also calculate information regarding the required uplink timing alignment to be used by the mobile terminal to time the target cell relative to the reference cell.

  Reporting specific timing difference information by the mobile terminal to the aggregation access point allows the aggregation access point to track the time alignment to be used by the mobile terminal for the uplink target cell Make it possible. Similarly, reporting the calculated information about the required uplink timing alignment to be used to time the target cell to the aggregation access point by the mobile terminal means that the aggregation access point It also realizes to know the time alignment to be used by the mobile terminal for the uplink target cell.

  The knowledge of time alignment to be used by the mobile terminal for the uplink target cell is advantageously used by the aggregation access point for various effects, as will become clear from the detailed embodiment description Can be done.

  One exemplary embodiment relates to a method for time alignment of uplink transmissions by mobile terminals in a mobile communication system. The mobile terminal communicates with the aggregation access point and is configured with an uplink reference cell with a fixed time and an uplink target cell with a non-timed.

  In this method, a mobile terminal measures transmission and / or reception time difference information related to transmissions on a target cell and / or a reference cell, and at least measured transmission and / or reception time difference information, and time is aligned. A first target timing advance is determined based on a reference timing advance used for uplink transmission on the reference cell, and an uplink target cell is determined based on the determined first target timing advance The uplink target cell time is aligned by adjusting the timing for uplink transmission above, and the measurement result and / or the first target timing advance is transmitted from the mobile terminal to the aggregation access point.

  According to an advantageous embodiment of the invention, which may be used additionally or alternatively to the above, the mobile terminal includes a timer included in the mobile terminal until otherwise ordered by the aggregation access point. (Ii) measuring transmission and / or reception time difference information; (ii) determining a first target timing advance; and (iii) aligning times of uplink target cells; , (Iv) transmitting the measurement result and / or the first target timing advance.

  According to an advantageous embodiment of the invention that may be used additionally or alternatively to the above, the aggregation access point may be configured in advance of the aggregation access point and / or the aggregation access Based on the evaluation step performed by the point, at least a random access channel, RACH, command message for the uplink target cell for instructing the mobile terminal to perform a random access procedure, and at least Aggregation access point based on received measurement results and / or received first target timing advance and reference timing advance used for uplink transmission on timed reference cell By The determined second target timing advance, at least the received measurement result and / or the received first target timing advance, and an uplink timed based on the first target timing advance A mobile terminal by transmitting at least one of a timing advance update command for an uplink target cell, including a target timing advance update value determined based on an uplink transmission timing on the target cell A separate instruction is given.

  According to an advantageous embodiment of the invention, which may be used additionally or alternatively to the above, if the aggregation access point sends a RACH command message, the mobile terminal , A random access procedure is performed on the uplink target cell to determine a third target timing advance value for uplink transmission on the uplink target cell, and within the random access procedure The uplink target cell times are aligned by adjusting timing for uplink transmission on the uplink target cell based on the received and determined third target timing advance.

  According to an advantageous embodiment of the invention that may be used additionally or alternatively to the above, the aggregation access point determines the second target timing advance and the second target timing When transmitting the advance to the mobile terminal, when the mobile terminal receives the second target timing advance, the mobile terminal is configured to transmit an uplink based on the second target timing advance received from the aggregation access point. Aligning the time of the uplink target cell by adjusting the timing for uplink transmission on the target cell is performed.

  According to an advantageous embodiment of the invention that may be used additionally or alternatively to the above, if the aggregation access point sends a timing advance update command for the uplink target cell, When the mobile terminal receives the timing advance update command, the mobile terminal performs a fourth based on the included target timing advance update value and the timing advance used for uplink transmission on the uplink target cell. The target timing advance of the uplink target cell is adjusted by adjusting the timing related to uplink transmission on the uplink target cell based on the determined fourth target timing advance.

  According to an advantageous embodiment of the invention, which may be used additionally or alternatively to the above, the mobile terminal is configured such that the mobile terminal transmits an uplink transmission on the uplink target cell of the reference cell. And / or when receiving from the aggregation access point information indicating that a time alignment different from the time alignment used for receiving is required, preferably as an RRC message comprising the target cell. A step of measuring reception time difference information and a step of determining a first target timing advance are executed. Alternatively, the step of measuring transmission and / or reception time difference information and the step of determining the first target timing advance include timings for the target cell that the mobile terminal is different from the timing advance group of the reference cell. It is also executed when information indicating the advance group is received from the aggregation access point.

  According to an advantageous embodiment of the invention that may be used additionally or alternatively to the above, the aggregation access point increases the reception time of uplink transmissions on the uplink target cell. Downlink on the corresponding downlink target cell by comparing with the predefined reference time for uplink transmission on the link target cell or the uplink transmission reception time on the uplink target cell Uplink on the uplink target cell by comparing with the transmission time of the transmission of the link or by comparing the received measurement result and / or the first target timing advance with a predefined threshold An evaluation step for determining transmission deviation is executed.

  If the determined deviation is greater than a predefined deviation threshold, the aggregation access point may receive at least one of a RACH command message, a second target timing advance, and a timing advance update command. To the mobile device.

  According to an advantageous embodiment of the invention that may be used additionally or alternatively to the above, the aggregation access point receives a measurement result and / or a first target timing advance. , And / or when the timer expires, is pre-configured to send at least one of a RACH command message, a second target timing advance, and a timing advance update command to the mobile terminal.

  According to an advantageous embodiment of the invention, which can be used additionally or alternatively to the above, the reference cell performs a random access procedure between the mobile terminal and the aggregation access point in the reference cell. First time is aligned by running.

According to an advantageous embodiment of the present invention, which may be used additionally or alternatively to the above, the mobile terminal starts with the start of the first downlink subframe (T _{DL_RX_SCell} ) on the target cell. Difference in downlink reception time (Δ _Scell-PCell Rx _DL ) between the target cell and the reference cell by measuring the time between the start of the corresponding downlink subframe on the reference cell (T _{DL_RX_PCell} ) And the downlink subframes on the reference cell and the target cell refer to the same subframe number. The measurement result may optionally be sent to the aggregation access point and includes a downlink reception time difference between the target cell and the reference cell.

According to an advantageous embodiment of the invention, which may be used additionally or alternatively to the above, the mobile terminal transmits time (T _{UL_TX_PCell)} when the mobile terminal transmits an uplink radio frame on the reference cell. ) And the time at which the mobile terminal receives the downlink radio frame on the target cell (T _{DL_RX_SCell} ) to measure the difference in reception transmission time between the target cell and the reference cell (Δ _Scell-PCell Rx the _{DL -Tx UL)} performs measurements by determining by the mobile terminal, the radio frame and the radio frame of the downlink of the uplink associated with the same radio frame. The measurement result may optionally be transmitted to the aggregation access point and includes a difference in received transmission time between the target cell and the reference cell.

According to an advantageous embodiment of the invention, which can be used additionally or alternatively to the above, the mobile terminal can be compared with the target cell by subtracting the reception transmission time difference from the timing advance of the reference cell. A first target timing advance is determined by determining a downlink reception time difference (Δ _Scell-PCell Rx _DL ) between reference cells.

  According to an advantageous embodiment of the invention, which may be used additionally or alternatively to the above, the mobile terminal determines the first target timing advance based on the difference in downlink reception time To do.

According to an advantageous embodiment of the invention, which may be used additionally or alternatively to the above, the aggregation access point can determine whether the downlink transmission time difference between the target cell and the reference cell ( The second target timing advance is determined based on ( _{ΔScell−PCell} Tx _DL ). The difference in downlink transmission time between the target cell and the reference cell is the start of the downlink subframe on the reference cell (T _{DL_TX_PCell} ) and the start of the corresponding downlink subframe on the target cell (T _{DL_TX_SCell} ). The downlink subframe refers to the same subframe number.

  According to an advantageous embodiment of the invention, which can be used additionally or alternatively to the above, each mobile terminal is configured to transmit uplink radio frames on the uplink target cell, respectively. A first target timing advance determined in consideration of being relative to the start of a downlink radio frame received via a downlink target cell; a second target timing advance; Using the third target timing advance or the fourth target timing advance, the transmission of the uplink radio frame on the uplink target cell is transmitted through the downlink target cell. The time of the target cell is aligned by setting it relative to the start of the radio frame.

  Alternatively, the mobile terminal may be configured to transmit an uplink radio frame on the uplink target cell relative to the start of the downlink radio frame received via the downlink reference cell. On the uplink target cell using the first target timing advance, the second target timing advance, the third target timing advance, or the fourth target timing advance determined in consideration of The time of the target cell is aligned by setting the transmission of the uplink radio frame relative to the start of the downlink radio frame received via the downlink reference cell.

  Alternatively, the mobile terminal may be configured to transmit uplink radio frames on the uplink target cell relative to the beginning of the uplink radio frame transmitted via the uplink reference cell. On the uplink target cell using the first target timing advance, the second target timing advance, the third target timing advance, or the fourth target timing advance determined in consideration of The time of the target cell is aligned by setting the transmission of the uplink radio frame relative to the beginning of the uplink radio frame transmitted via the uplink reference cell.

  According to an advantageous embodiment of the invention, which can be used additionally or alternatively to the above, the mobile terminal transmits the measurement result to the aggregation access access on the physical uplink shared channel, PUSCH of the reference cell. Send to point.

  According to an advantageous embodiment of the invention, which can be used additionally or alternatively to the above, the mobile terminal sends the measurement result to one of the radio resource control layer, RRC or medium access control layer, MAC. If the measurement result is part of the MAC layer, the measurement result is preferably transmitted within the MAC control element.

According to an advantageous embodiment of the invention, which may be used additionally or alternatively to the above content, measuring time difference information by the mobile terminal and transmitting the measurement result to the aggregation access point And
● Run periodically and / or ● i. Configuration and / or activation of the target cell,
ii. The measurement result exceeds a predetermined threshold,
iii. Timing advance timer expires,
iv. Receiving a request for a measurement report from an aggregation access point;
Triggered by a predetermined event such as

According to an advantageous embodiment of the invention that can be used additionally or alternatively to the above, the request for a measurement report from the aggregation access point is:
A deactivation / activation command for deactivating / activating a configured cell, including a flag indicating a request for a measurement report, the flag being reserved for the deactivation / activation command Deactivation / activation command, preferably set to one of the bits, or ● Radio resource control connection reconfiguration message containing a flag indicating a request for measurement report, or ● Random access channel, RACH A command message, or a random access channel, RACH, command message with a predetermined code point or a predetermined combination of code points indicating a request for a measurement report.

  According to an advantageous embodiment of the invention, which may be used additionally or alternatively to the above, the aggregation access point when the aggregation access point determines the second target timing advance. The point transmits a second target timing advance within the medium access control, MAC, control element, preferably the second target timing advance is transmitted using a downlink shared channel.

  According to an advantageous embodiment of the invention, which may be used additionally or alternatively to the above, the second target when the aggregation access point determines the second target timing advance. Timing advance is an absolute that is not used in relation to the reference timing advance value of the reference cell because the step of aligning the time of the uplink target cell is based only on the absolute value of the second target timing advance. Value. Alternatively, the second target timing advance is a relative used relative to the reference timing advance value of the reference cell because the step of aligning the time of the uplink target cell is also based on the reference timing advance. Value.

  According to an advantageous embodiment of the invention that may be used additionally or alternatively to the above, the reference cell is a primary cell or one of a plurality of secondary cells. The target cell is one of a plurality of secondary cells.

  According to an advantageous embodiment of the invention that may be used additionally or alternatively to the above, the mobile terminal is based on the same second target timing advance received from the aggregation access point The same as determined by the mobile terminal based on the same first target timing advance determined by the mobile terminal or when receiving a timing advance update command for uplink transmission on the uplink target cell Based on the fourth target timing advance, a step of aligning the time with respect to each target cell of the timing advance group, which is one of the plurality of target cells forming the group, is executed.

  According to an advantageous embodiment of the invention that can be used additionally or alternatively to the above, the mobile terminal is composed of target cells that do not have a plurality of times, and the mobile terminal Time alignment according to one of the various exemplary embodiments described herein.

  According to an advantageous embodiment of the invention, which can be used additionally or alternatively to the above, the mobile terminal can determine the measurement results for each of the target cells, preferably all configured secondary cells. Or send to the aggregation access point in one message for all secondary cells to be configured and activated.

  The present invention further provides a mobile terminal for aligning uplink transmission times in a mobile communication system. The mobile terminal communicates with the aggregation access point and is configured with an uplink reference cell with a fixed time and an uplink target cell with a non-timed. The mobile terminal processor measures transmission and / or reception time difference information associated with transmissions on the target cell and / or reference cell. The processor determines a first target timing advance based at least on measured transmission and / or reception time difference information and a reference timing advance used for uplink transmission on the timed reference cell. To do. The transmitter of the mobile terminal aligns the time of the uplink target cell by adjusting the timing for uplink transmission on the uplink target cell based on the determined first target timing advance. The transmitter transmits the measurement result and / or the first target timing advance from the mobile terminal to the aggregation access point.

  According to an advantageous embodiment of the invention that can be used additionally or alternatively to the above, based on a timer, the processor and transmitter of the mobile terminal measure transmission and / or reception time difference information. Determining the first target timing advance, aligning the time of the uplink target cell, and transmitting the measurement result and / or the first target timing advance. Repeat until the receiver of the mobile terminal receives a command from the aggregation access point that gives a separate command.

  According to an advantageous embodiment of the invention that can be used additionally or alternatively to the above, the receiver of the mobile terminal receives the RACH command message from the aggregation access point. When the processor, transmitter, and receiver receive the RACH command message, the processor, transmitter, and receiver are randomly selected in the uplink target cell to determine a third target timing advance value for uplink transmission on the uplink target cell.・ Execute the access procedure. The processor and transmitter receive the uplink target by adjusting timing for uplink transmission on the uplink target cell based on the third target timing advance received and determined within the random access procedure. Align cell times.

  According to an advantageous embodiment of the invention that may be used additionally or alternatively to the above, the receiver of the mobile terminal receives a second target timing advance from the aggregation access point . When the processor and transmitter receive the second target timing advance, timing for uplink transmission on the uplink target cell based on the second target timing advance received from the aggregation access point Align the uplink target cell time by adjusting.

  According to an advantageous embodiment of the invention, which can be used additionally or alternatively to the above, the mobile terminal receiver receives a timing advance update command for the uplink target cell. When the processor receives the timing advance update command, the processor sets a fourth target based on the included target timing advance update value and the timing advance used for uplink transmission on the uplink target cell. Determine timing advance. The processor and transmitter then align the uplink target cell time by adjusting timing for uplink transmission on the uplink target cell based on the determined fourth target timing advance.

  According to an advantageous embodiment of the invention, which can be used additionally or alternatively to the above, according to an advantageous embodiment of the mobile terminal, the uplink transmission on the uplink target cell is for the reference cell. When receiving from the aggregation access point information indicating that a time alignment different from the time alignment used for the target cell is required, preferably as an RRC message comprising the target cell, or the timing of the reference cell When receiving information indicating a timing advance group related to a target cell different from the advance group from the aggregation access point, the processor and the transmitter measure transmission and / or reception time difference information, and the processor , Determine the first target timing advance It is adapted to.

  According to an advantageous embodiment of the invention, which can be used additionally or alternatively to the above, the reference cell comprises a processor, a transmitter, and a receiver with the mobile terminal in the reference cell. Initially timed by performing a random access procedure between points.

According to an advantageous embodiment of the invention, which may be used additionally or alternatively to the above, the processor starts the first downlink subframe ( _{TDL_RX_SCell} ) and the reference on the target cell. The difference in downlink reception time (Δ _Scell-PCell Rx _DL ) between the target cell and the reference cell by measuring the time between the beginning of the corresponding downlink subframe on the cell (T _{DL_RX_PCell} ) Determine and downlink subframes on the reference cell and the target cell refer to the same subframe number, and optionally, the transmitter measures the difference in downlink reception time between the target cell and the reference cell Adapted to transmit to the aggregation access point.

According to an advantageous embodiment of the invention, which may be used additionally or alternatively to the above, the time for the mobile terminal to transmit an uplink radio frame on the reference cell (T _{UL_TX_PCell} ) the received transmission time (Δ _{Scell-PCell Rx DL} between the target cell and the reference cell by measuring the time difference between the time the mobile terminal receives the radio frame of the downlink on the target cell _{(T DL_RX_SCell)} -Tx _UL ), the uplink radio frame and the downlink radio frame are related to the same radio frame, and optionally the transmitter determines the difference in received transmission time between the target cell and the reference cell. It is adapted to send the measurement result to the aggregation access point.

According to an advantageous embodiment of the invention, which can be used additionally or alternatively to the above, the processor can determine whether the reference cell and the reference cell by subtracting the reception transmission time difference from the reference cell timing advance. _Determine the difference in downlink reception time between cells (Δ _Scell-PCell Rx _DL ).

  According to an advantageous embodiment of the invention that may be used additionally or alternatively to the above, the processor determines a first target timing advance based on the difference in downlink reception time .

  According to an advantageous embodiment of the invention, which may be used additionally or alternatively to the above, the processor and the transmitter respectively transmit uplink radio frames on the uplink target cell. A first target timing advance, a second target timing, determined in consideration of the setting being relative to the start of the downlink radio frame received via the downlink target cell; An uplink, a third target timing advance, or a fourth target timing advance is used to transmit an uplink radio frame transmission on the uplink target cell received via the downlink target cell. The time of the target cell is aligned by setting relative to the start of the radio frame of the link.

  Alternatively, the processor and transmitter may configure the transmission of the uplink radio frame on the uplink target cell relative to the start of the downlink radio frame received via the downlink reference cell. An uplink target cell using the first target timing advance, the second target timing advance, the third target timing advance, or the fourth target timing advance determined in consideration of The time of the target cell is aligned by setting the transmission of the upper uplink radio frame relative to the beginning of the downlink radio frame received via the downlink reference cell.

  Alternatively, the processor and the transmitter may be configured such that the configuration of uplink radio frame transmission on the uplink target cell is relative to the beginning of the uplink radio frame transmitted via the uplink reference cell. An uplink target cell using the first target timing advance, the second target timing advance, the third target timing advance, or the fourth target timing advance determined in consideration of The time of the target cell is aligned by setting the transmission of the upper uplink radio frame relative to the beginning of the uplink radio frame transmitted via the uplink reference cell.

  According to an advantageous embodiment of the invention, which can be used additionally or alternatively to the above, the transmitter transmits the measurement results to the aggregation access access on the physical uplink shared channel, PUSCH of the reference cell. Send to point.

  According to an advantageous embodiment of the invention that may be used additionally or alternatively to the above, the transmitter transmits the measurement result to one of the radio resource control layer, RRC or medium access control layer, MAC. If the measurement result is part of the MAC layer, the measurement result is preferably transmitted within the MAC control element.

According to an advantageous embodiment of the invention which may be used additionally or alternatively to the above, the processor and the transmitter are
● Periodically and / or ● i. Configuration and / or activation of the target cell,
ii. The measurement result exceeds a predetermined threshold,
iii. Timing advance timer expires,
iv. Receiving a request for a measurement report from an aggregation access point;
By a predetermined event such as
Time difference information is measured to determine a first target timing advance, and the measurement result and / or the first target timing advance is transmitted to the aggregation access point.

According to an advantageous embodiment of the invention, which can be used additionally or alternatively to the above, the receiver
A deactivation / activation command as a measurement report request from an aggregation access point to deactivate / activate a configured cell, including a flag indicating a measurement report request; The flag is preferably set to one of the reserved bits of the deactivation / activation command, a deactivation / activation command, or an aggregation Radio resource control connection reconfiguration message as request for measurement report from access point, or ● Random access channel, RACH, command message as request for measurement report from aggregation access point, or ● Measurement report Having a combination of prearranged Predetermined code point or code point indicating a request, receiving a random access channel, RACH, an instruction message as a request for a measurement report from the aggregation access point.

  According to an advantageous embodiment of the invention that may be used additionally or alternatively to the above, the reference cell is a primary cell or one of a plurality of secondary cells. The target cell is one of a plurality of secondary cells.

  According to an advantageous embodiment of the invention, which may be used additionally or alternatively to the above, the processor and the transmitter receive the same second target timing advance received from the aggregation access point. Based on the same first target timing advance determined by the mobile terminal or determined by the mobile terminal when receiving a timing advance update command for uplink transmission on the uplink target cell Based on the same fourth target timing advance, the time of each target cell of the timing advance group is aligned.

  According to an advantageous embodiment of the invention that may be used additionally or alternatively to the above, if the mobile terminal is configured with target cells that do not have a plurality of times, the mobile terminal Time alignment according to one of the various exemplary embodiments described herein is performed for each of the target cells.

  According to an advantageous embodiment of the invention, which can be used additionally or alternatively to the above, the transmitter can measure the measurement results for each of the target cells, preferably for all secondary cells that are configured. Or send to the aggregation access point in one message for all secondary cells to be configured and activated.

The present invention further provides an aggregation access point for controlling time alignment of mobile terminals in a mobile communication system, wherein the mobile terminal communicates with the aggregation access point and is time aligned uplink Reference cells and uplink target cells that do not have the same time. The aggregation access point memory stores the pre-configuration. The receiver of the aggregation access point receives the measurement result and / or the first target timing advance. The aggregation access point processor may receive at least the received measurement results and / or the received first target timing advance, and the reference timing used for uplink transmission on the timed reference cell. The determination of the advance and / or at least the received measurement result and / or the received first target timing advance and the time aligned uplink based on the first target timing advance It is adapted to make a decision based on the timing of uplink transmissions on the target cell. Based on the pre-configuration of the aggregation access point and / or the processor performing the evaluation step, the transmitter
A random access channel, RACH, command message for the uplink target cell to command the mobile terminal to perform a random access procedure; and
Determined by the processor based on at least the received measurement results and / or the received first target timing advance and the reference timing advance used for transmission of the uplink on the timed reference cell Second target timing advance made,
At least the received measurement results and / or the received first target timing advance and the timing of the uplink transmission on the uplink target cell timed based on the first target timing advance Instructing the mobile terminal to separately instruct the mobile terminal by sending at least one of a timing advance update command for the uplink target cell, including a target timing advance update value determined based on Can be sent.

  According to an advantageous embodiment of the invention, which may be used additionally or alternatively to the above, the processor determines the reception time of the uplink transmission on the uplink target cell. By comparing the reception time of the uplink transmission on the uplink target cell by comparing it with a predefined reference time for the uplink transmission on the corresponding downlink transmission on the target cell The uplink transmission deviation on the uplink target cell by comparing with the transmission time or by comparing the received measurement result and / or the first target timing advance with a predefined threshold. An evaluation step for determining is executed.

  If the determined deviation is greater than a predefined deviation threshold, the transmitter sends at least one of a RACH command message, a second target timing advance, and a timing advance update command to the mobile terminal. Send.

  According to an advantageous embodiment of the invention, which may be used additionally or alternatively to the above, the aggregation access point is used by the transmitter, the measurement result and / or the first target timing advance. And / or when the timer expires based on the memory to send at least one of a RACH command message, a second target timing advance, and a timing advance update command to the mobile terminal Pre-configured.

According to an advantageous embodiment of the invention, which may be used additionally or alternatively to the above, the processor transmits the difference in downlink transmission time (Δ _Scell-PCell between the target cell and the reference cell). Tx _DL ) is further adapted to determine a second target timing advance, and the downlink transmission time difference between the target cell and the reference cell is determined by the beginning of the downlink subframe on the reference cell. It is the time difference between (T _{DL_TX_PCell} ) and the start of the corresponding downlink subframe (T _{DL_TX_SCell} ) on the target cell, where the downlink subframes point to the same subframe number.

  According to an advantageous embodiment of the invention that may be used additionally or alternatively to the above, the transmitter transmits a second target timing advance in the medium access control, MAC, control element. Preferably, however, the step of transmitting the second target timing advance uses a downlink shared channel.

  According to an advantageous embodiment of the invention that may be used additionally or alternatively to the above, the processor determines a second target timing advance, the second target timing advance being: An absolute value that is not used in relation to the reference timing advance value of the reference cell, or a relative value where the second target timing advance is used relative to the reference timing advance value of the reference cell Value.

  The present invention further provides a computer readable medium storing instructions that, when executed by a processor of a mobile terminal, cause the mobile terminal to align uplink transmission times in a mobile communication system as follows. Transmission and / or reception time difference information related to transmissions on the target cell and / or reference cell is measured. A first target timing advance based on at least measured transmission and / or reception time difference information and a reference timing advance used for uplink transmission on the timed reference cell is determined. The uplink target cells are timed by adjusting timing for uplink transmission on the uplink target cell based on the determined first target timing advance. A measurement result from the mobile terminal and / or a first target timing advance is transmitted to the aggregation access point.

  The computer readable medium stores instructions that, when executed by a processor of the mobile terminal, cause the mobile terminal to perform the method steps described above.

  In accordance with another aspect of the present invention, the mobile terminal is configured in the uplink where the time of the radio cell is not aligned relative to the reference cell in which the (reference) uplink component carrier is already time aligned.・ Align component and carrier time. Therefore, the determination of timing advance for time alignment of uplink component carriers whose radio cells are not aligned is determined by the timing advance for the reference cell (uplink component carrier), the reference cell and Based on the time difference of the reception time of the corresponding downlink transmission by the downlink component carrier of the radio cell including the uplink component carrier that is not in time (hereinafter also referred to as “reception time difference”) It is determined.

  As can be seen, the time alignment of the uplink component carrier that is not aligned is relative to the reception timing of the downlink component carrier of the reference cell or its uplink component carrier. Can be executed relative to the reception timing of the downlink component carrier of the radio cell.

  One exemplary embodiment of the present invention relates to a method for time alignment of uplink transmissions by mobile terminals in a mobile communication system. The mobile terminal includes a first radio cell that includes a downlink component carrier and a timed uplink component carrier, and a downlink component carrier and a timed uplink component carrier It consists of a second radio cell.

  In this method, a mobile terminal is brought down from an aggregation access point to a mobile terminal via a downlink component carrier of a first radio cell and a downlink component carrier of a second radio cell, respectively. Determining the difference in reception time (or difference in propagation delay) for transmission of the link from the mobile terminal via the uplink component carrier of the first radio cell and the uplink component carrier of the second radio cell For uplink transmissions on the uplink component carrier timed of the first radio cell so that uplink transmissions transmitted to the aggregation access point arrive at the aggregation access point simultaneously Timing The second by adjusting the timing advance for uplink transmission on the uplink component carrier of the second radio cell based on the advance and the determined difference in reception time (or difference in propagation delay). Align radio component uplink component carrier time.

  In one exemplary implementation of this embodiment, the downlink component carrier and the uplink component carrier of one of the radio cells are, for example, between the aggregation access point and the mobile terminal. While the downlink component carrier and uplink component carrier of the other radio cell may be established between another access point and the mobile terminal.

  Another access point has a bi-directional interface to the aggregation access point, for example, transmissions from the mobile terminal are forwarded to the aggregation access point and transmissions to the mobile terminal are forwarded to the mobile terminal there is a possibility.

  In this exemplary implementation, the determined reception time difference (or propagation delay difference) determined by the mobile terminal is, for example, propagation of transmission between an aggregation access point and another access point. The delay, the processing delay of another access point to process the transmission to be forwarded, and the propagation delay of the transmission between another access point and the mobile terminal can be taken into account.

  In one exemplary implementation, the aggregation access point may be an eNodeB. In another implementation, another access point may be, for example, a frequency selective repeater (FSR), or a remote radio head (RRH) controlled by an aggregation access point.

  According to a further embodiment of the invention, uplink data is transmitted by the mobile terminal to the aggregation access point via the timed first component carrier and the timed second component carrier. The aggregation access point combines the uplink transmissions of the mobile terminal received via the timed first component carrier and the timed second component carrier.

  The combination of uplink transmissions by the aggregation access point may be performed at one of various layers. For example, the uplink data combination of the mobile terminal may be performed by the RLC entity of the aggregation access point. This may be the case, for example, in a scenario where the aggregation access point is eNodeB and another access point is RRH.

  Alternatively, the uplink data combination of the mobile terminal is performed by the physical layer entity of the aggregation access point. This may be the case, for example, in a scenario where the aggregation access point is an eNodeB and another access point is an FSR.

  There are different possibilities of how the uplink component carrier of the first radio cell will be timed. In one exemplary embodiment of the present invention, a random access procedure in which an uplink component carrier of a first radio cell constitutes a timing advance for the uplink component carrier of the first radio cell. By performing (also referred to as RACH procedure), the time is aligned by the mobile terminal and the access point. Advantageously, the uplink component carrier of the second radio cell is timed without performing a random access procedure with the access point. In one exemplary embodiment, the access point that performs the RACH procedure with the mobile terminal is an aggregation access point.

  In one exemplary implementation, the mobile terminal uses an aggregate access access to time the uplink component carrier of the second radio cell based on the difference in reception time (or difference in propagation delay). Receive command from point. For example, the command may be included in an RRC radio resource configuration message.

  The command may be, for example, whether the mobile terminal should use a random access procedure to time the uplink component carrier of the second radio cell, or the downlink component carrier of the reference radio cell (I.e., using the above terminology, the second radio cell up based on the difference in reception time (or difference in propagation delay) relative to the downlink component carrier of the first cell) It may be signaled by a flag indicating whether the time of link component carriers should be aligned.

  In a further embodiment of the present invention, the mobile terminal determining the difference in reception time (or difference in propagation delay) for downlink transmission is received via the downlink component carrier of the first cell. The difference in reception time (or propagation delay difference) is calculated by subtracting the start time of the subframe received via the downlink component carrier of the second cell from the start time of the next subframe. Including doing. The start of the next subframe is received via the downlink component carrier of the first cell after the time of the start of the subframe received via the downlink component carrier of the second cell. Signifies the beginning of the next subframe to be played.

  In another embodiment of the invention, to align the time of the mobile node's uplink component carrier, the mobile node has, for example, a respective timing advance value for each uplink component carrier. there's a possibility that. In an alternative embodiment of the present invention, multiple component carriers may have the same propagation delay, and these component carriers may be grouped and associated with their respective timing advance values. There are scenarios that are considered. Thus, in this case, the mobile node has, for example, a respective timing advance value for each group of one or more uplink component carriers, and one or more uplink component carriers of the group The uplink transmission above suffers the same propagation delay.

  In a further exemplary implementation, timing advance values for uplink component carriers ensure that uplink transmissions over those uplink component carriers arrive at the aggregation access point simultaneously. To be determined.

  In one exemplary embodiment, the timing advance value for the uplink component carrier of a given radio cell is the downlink component of the given radio cell (eg, the second radio cell described above). It may be considered to indicate a time shift for the transmission of uplink subframes on the uplink component carrier of a given radio cell relative to the beginning of the subframe received over the carrier . In an alternative embodiment of the invention, the timing advance value for the uplink component carrier of a given radio cell is the downlink component carrier of the reference cell (eg, the first radio cell described above). Can be considered to indicate a time shift relative to the transmission of uplink subframes on the uplink component carrier of a given radio cell relative to the beginning of the subframe received via.

In one exemplary embodiment of the invention, aligning the time of the uplink component carrier of the second radio cell is the timing for the uplink component carrier of the time of the first radio cell. - the advance value TA _AP1, as follows timing advance value TA _AP2 about uplink component carrier of the second cell based on the determined (difference or propagation delay) difference between the received time was [Delta] T _prop Including calculating.
TA _AP2 = TA _AP1 + 2 · ΔT _prop

In this exemplary embodiment, the timing advance value TA _AP2 is relative to (or more strictly speaking, the second radio cell downlink component carrier reception timing). Define a timing advance (relative to the reception timing of the beginning of the subframe transmitted over the downlink component carrier of the radio cell).

In another exemplary embodiment of the present invention, the time alignment of the uplink component carrier of the second radio cell is the timing for the time aligned uplink component carrier of the first radio cell. - the advance value TA _AP1, as follows timing advance value TA _AP2 about uplink component carrier of the second cell based on the determined (difference or propagation delay) difference between the received time was [Delta] T _prop Including calculating.
TA _AP2 = TA _AP1 + ΔT _prop

In this exemplary embodiment, the timing advance value TA _AP2 is relative to (or more strictly speaking, the first radio cell downlink component carrier reception timing) Define a timing advance (relative to the reception timing at the beginning of the subframe transmitted over the downlink component carrier of the radio cell).

  Another third aspect of the present invention is to propose a procedure for time alignment of uplink component carriers for use in a mobile terminal handover procedure. The time alignment procedure discussed above can also be used to time uplink component carriers in a radio cell controlled by a handover destination (aggregation) access point to which a mobile terminal is handed over. According to this aspect, a timing advance for one of the uplink component carriers in the radio cell (ie, reference cell) of the handover destination (aggregation) access point can be provided to the mobile terminal (synchronized) Handover) or can be determined by the mobile terminal, for example by performing a random access procedure (asynchronous handover). The other uplink component carrier (s) of the other radio cell (s) to be used by the mobile terminal is then the reference cell as previously described herein. Can be relatively time aligned.

  In accordance with this third aspect, and in accordance with a further embodiment of the present invention, a method is provided for performing a handover of a mobile terminal to a handover destination access point (eg, eNodeB). The mobile terminal includes a first radio cell including a downlink component carrier and an uplink component carrier, a downlink component carrier and an uplink component under the control of a handover destination aggregation access point. -It is comprised with the 2nd radio | wireless cell containing a carrier.

  The mobile terminal performs a random access procedure with the handover destination aggregation access point, thereby aligning the uplink component carrier time of the first radio cell. At that time, the mobile terminal transmits the downlink from the handover destination access point to the mobile terminal via the downlink component carrier of the first radio cell and the downlink component carrier of the second radio cell. A difference in reception time for transmission (or difference in propagation delay) can be determined, and the mobile terminal via the uplink component carrier of the first radio cell and the uplink component carrier of the second radio cell Of uplink transmissions on the uplink component carrier timed in the first radio cell so that uplink transmissions transmitted from the to the aggregation access point arrive at the aggregation access point simultaneously For thailand By adjusting the timing advance for uplink transmission on the uplink component carrier of the second radio cell based on the determined advance and difference in received time (or difference in propagation delay) The time of the uplink component carrier of the second radio cell can be aligned.

  Also according to this third aspect, and according to another embodiment of the present invention, a method for performing a handover of a mobile terminal from a handover source access point to a handover destination aggregation access point is provided. Is done. The mobile terminal includes a first radio cell including a downlink component carrier and an uplink component carrier, a downlink component carrier and an uplink component under the control of a handover destination aggregation access point. It is still assumed that it is configured with a second radio cell including a carrier.

  In this usage, the mobile terminal should be applied by the mobile terminal for uplink transmission on the uplink component carrier of the first radio cell through the radio cell controlled by the handover source access point. A timing advance value indicating time alignment is received. Further, the mobile terminal transmits a downlink from the handover destination aggregation access point to the mobile terminal via the downlink component carrier of the first radio cell and the downlink component carrier of the second radio cell. The difference in reception time (or the difference in propagation delay) can be determined. Then, the uplink transmission transmitted from the mobile terminal to the aggregation access point via the uplink component carrier of the first radio cell and the uplink component carrier of the second radio cell is aggregated access. The difference between the time advance of the uplink component on the first radio cell timed to arrive at the point at the same time, and the determined reception time (or propagation delay) The time component of the uplink component carrier of the second radio cell by adjusting the timing advance for the transmission of the uplink on the uplink component carrier of the second radio cell based on be able to.

  The handover source access point and the handover destination aggregation access point may be eNodeB, for example.

  In another embodiment, the two handover methods described above provide a time for uplink transmission by a mobile terminal in a mobile communication system according to one of the various exemplary embodiments described herein. It may further comprise method steps for aligning.

  Another embodiment of the present invention relates to a mobile terminal for aligning uplink transmission times in a mobile communication system. The mobile terminal includes a first radio cell that includes a downlink component carrier and a timed uplink component carrier, and a downlink component carrier and a timed uplink component carrier It consists of a second radio cell. In this embodiment, the mobile terminal has a receiver unit adapted to receive downlink transmissions, a downlink component carrier of a first radio cell and a downlink component carrier of a second radio cell, respectively. And a processing unit adapted to determine a difference in reception time (or difference in propagation delay) for downlink transmission from the aggregation access point to the mobile terminal via the component carrier. The processing unit is based on the timing advance for the uplink transmission on the uplink component carrier timed in the first radio cell and the determined difference in reception time (or difference in propagation delay). Align the time of the uplink component carrier of the second radio cell by adjusting the timing advance for uplink transmission on the uplink component carrier of the second radio cell. In addition, the mobile terminal may perform aggregate access for uplink transmission through the uplink component carrier having the same time in the first radio cell and the uplink component carrier having the same time in the second radio cell. Aggregation access point via uplink component carrier timed in the first radio cell and uplink component carrier timed in the second radio cell to arrive at the point simultaneously Includes a transmitter unit adapted to transmit uplink transmissions.

  A mobile terminal according to a more detailed embodiment of the present invention is adapted to perform a handover to an aggregation point. The receiver unit of the mobile terminal is time to be applied by the mobile terminal for uplink transmission on the uplink component carrier of the first radio cell through the radio cell controlled by the handover source access point. Adapted to receive a timing advance value indicating alignment.

  In an alternative implementation, the mobile terminal performs a handover from the handover source access point to the aggregation point and performs a random access procedure with the aggregation access point, thereby causing the first radio cell's Adapted to align uplink component carrier time.

  Another embodiment of the present invention, when executed by a processor of a mobile terminal, is directed to the mobile terminal by the mobile terminal, respectively, the downlink component carrier of the first radio cell and the downlink of the second radio cell. Determining a difference in reception time (or difference in propagation delay) for transmission of a downlink from an aggregation access point to a mobile terminal via a component carrier, wherein the mobile terminal Consists of a first radio cell including an uplink component carrier with a carrier and a time aligned, and a second radio cell including an uplink component carrier with a downlink component carrier and a non-time aligned Judgment And the uplink transmission transmitted from the mobile terminal to the aggregation access point via the uplink component carrier of the first radio cell and the uplink component carrier of the second radio cell. The time component of the first radio cell to arrive at the point at the same time, the timing advance for the transmission of the uplink on the carrier and the difference between the determined reception times (or the propagation delay) Aligning the time of the uplink component carrier of the second radio cell by adjusting the timing advance for uplink transmission on the uplink component carrier of the second radio cell based on the difference) By Moby It is to provide a computer-readable medium storing instructions that cause align the transmission of uplink time in a communication system.

  A computer-readable medium according to a further embodiment of the present invention, when executed by a processor of a mobile terminal, in a mobile communication system according to one of the various exemplary embodiments described herein. Instructions are stored that cause the steps of the method for aligning uplink transmission times by the mobile terminal to be executed.

  According to a fourth aspect, the present invention makes it possible to align the time for uplink transmissions for uplink cells that are not aligned (hereinafter referred to as target cells) with respect to the reference cell, Are already timed and controlled by the same or different aggregation access points as the target cell. It is assumed that at least one existing cell is already in time and serves as a reference cell for the time alignment procedure of the present invention. Advantageously, instead of performing a RACH procedure on the target cell to align the time, the present invention provides a different approach in this regard.

  More specifically, the mobile terminal measures specific timing difference information and reports the measurement results to the aggregation access point, thereby adjusting the timing of the uplink target cell for which time is not aligned. Supports calculation of advance values. Specific timing difference information measured by the mobile terminal allows the aggregation access point to estimate the required uplink timing alignment that the mobile terminal uses for the target cell when it receives the information. Is something.

  The aggregation access point then calculates information regarding the required uplink timing alignment used by the mobile terminal to align the time of the target cell with respect to a reference cell that is already in time. In order to calculate the timing advance, the aggregation access point uses at least the measurements received from the mobile terminal and the timing advance of the reference cell.

  Subsequently, the aggregation access point transmits a timing advance command to the mobile terminal, and this time, the mobile terminal uses the received timing advance command information to transmit an uplink for the target cell. Align the time.

  The timing advance command may include information on an absolute timing advance value for the target cell or a relative timing advance value relative to a reference cell timing advance value (a value known to the mobile terminal). In any case, the mobile terminal receives the received timing advance so that uplink transmissions transmitted on the target cell from the mobile terminal to the aggregation access point arrive at the aggregation access point synchronously. According to the command, the transmission timing of the uplink transmission of the uplink of the target cell can be adjusted.

  The present invention provides a method for aligning uplink transmission times by a mobile terminal in a mobile communication system. The mobile terminal communicates with the aggregation access point and is configured with an uplink reference cell having a uniform time and an uplink target cell having a non-timed. The mobile terminal measures transmission and / or reception time difference information related to transmissions on the target cell and / or reference cell. The measurement result is transmitted from the mobile terminal to the aggregation access point. The aggregation access point determines a target timing advance based at least on the received measurement results and the reference timing advance used for uplink transmission on the timed reference cell. The aggregation access point transmits the target timing advance to the mobile terminal. The mobile terminal aligns the time of the uplink target cell by adjusting the timing for uplink transmission on the uplink target cell based on the target timing advance received from the aggregation access point.

  According to an advantageous embodiment of the invention, which can be used additionally or alternatively to the above, the reference cell has random access between the mobile terminal and the aggregation access point on the reference cell. By executing the procedure, you can get time aligned first.

According to an advantageous embodiment of the invention which may be used additionally or alternatively to the above, the step of measuring by the mobile terminal is the beginning of the first downlink subframe on the target cell ( by measuring the time between T _{DL_RX_SCell)} and the corresponding start of downlink subframe on the reference cell _{(T DL_RX_PCell),} the difference between the reception time of the downlink between the target cell and the reference cell (delta _Scell the _{-PCell Rx DL)} comprises determining by the mobile terminal, downlink subframe on the reference and target cells refer to the same sub-frame number. Optionally, the measurement result transmitted to the aggregation access point includes a difference in downlink reception time between the target cell and the reference cell.

According to an advantageous embodiment of the invention, which may be used additionally or alternatively to the above, the step of measuring by the mobile terminal is that the mobile terminal has transmitted an uplink radio frame on the reference cell by the time _{(T UL_TX_PCell)} the mobile terminal measures the time difference between the time upon receipt of a radio frame of the downlink on the target cell _{(T DL_RX_SCell),} the difference between the received transmission time between the target cell and the reference cell The method further includes determining (Δ _Scell-PCell Rx _DL -Tx _UL ) by the mobile terminal, wherein the uplink radio frame and the downlink radio frame are related to the same radio frame. Optionally, the measurement result transmitted to the aggregation access point includes a difference in reception transmission time between the target cell and the reference cell.

According to an advantageous embodiment of the invention which may be used additionally or alternatively to the above, the step of determining the target timing advance comprises the difference of the reception and transmission time from the reference cell timing advance. The method further includes determining a downlink reception time difference (Δ _{Scell−PCell} Rx _DL ) between the target cell and the reference cell by subtraction.

  According to an advantageous embodiment of the invention that may be used additionally or alternatively to the above, the step of determining the target timing advance is based on the difference in downlink reception times.

According to an advantageous embodiment of the invention that may be used additionally or alternatively to the above, the step of determining the target timing advance comprises the transmission time of the downlink between the target cell and the reference cell (Δ _{Scell−PCell} Tx _DL ). The difference in downlink transmission time between the target cell and the reference cell is the start of the downlink subframe on the reference cell (T _{DL_TX_PCell} ) and the start of the corresponding downlink subframe on the target cell (T _{DL_TX_SCell} ). The downlink subframe refers to the same subframe number.

  According to an advantageous embodiment of the invention that may be used additionally or alternatively to the above, the step of time alignment of the target cell is the transmission of uplink radio frames on the uplink target cell. Each of the uplink settings using the target timing advance determined by the aggregation access point deemed relevant to the beginning of the downlink radio frame received via the downlink target cell. Setting up transmission of an uplink radio frame on the target cell in relation to the beginning of a downlink radio frame received via the downlink target cell. Alternatively, the step of aligning the time of the target cell is that the setting of the transmission of the uplink radio frame on the uplink target cell is related to the start of the downlink radio frame received via the downlink reference cell. Downlink receiving uplink radio frame transmission on the uplink target cell via the downlink reference cell using the target timing advance determined by the considered aggregation access point Setting in relation to the start of the radio frame. Alternatively, the step of aligning the time of the target cell is that the configuration of the transmission of the uplink radio frame on the uplink target cell is related to the beginning of the uplink radio frame transmitted via the uplink reference cell. The uplink radio frame transmission on the uplink target cell is transmitted via the uplink reference cell using the target timing advance determined by the considered aggregation access point. Setting in relation to the start of the radio frame.

  According to an advantageous embodiment of the invention that may be used additionally or alternatively to the above, the measurement results are transmitted to the aggregation access point on the physical uplink shared channel PUSCH of the reference cell. Is done.

  According to an advantageous embodiment of the invention that may be used additionally or alternatively to the above, the step of transmitting the measurement result is part of a radio resource control layer RRC or a medium access control layer MAC. Yes, if it is part of the MAC layer, the measurement results are preferably transmitted within the MAC control element.

According to an advantageous embodiment of the invention, which may be used additionally or alternatively to the above, measuring the time difference information by the mobile terminal and sending the measurement result to the aggregation access point comprises:
● Run periodically and / or v. Configuration and / or activation of the target cell,
vi. The measurement result exceeds a predetermined threshold,
vii. Timing advance timer expires,
viii. Receiving a request for a measurement report from an aggregation access point;
Triggered by a predetermined event such as

According to an advantageous embodiment of the invention that can be used additionally or alternatively to the above, the request for a measurement report from the aggregation access point is:
A deactivation / activation command for deactivating / activating a configured cell, including a flag indicating a request for a measurement report, the flag being reserved for the deactivation / activation command Deactivation / activation command, preferably set to one of the bits, or ● Radio resource control connection reconfiguration message containing a flag indicating a request for measurement report, or ● Random access channel, RACH A command message, or a random access channel, RACH, command message with a predetermined code point or a predetermined combination of code points indicating a request for a measurement report.

  According to an advantageous embodiment of the invention, which may be used additionally or alternatively to the above, the step of sending the target timing advance comprises the target timing advance in the medium access control MAC control element. Preferably, the target timing advance is transmitted using a downlink shared channel.

  According to an advantageous embodiment of the invention that may be used additionally or alternatively to the above, the target timing advance is determined based on the absolute value of the target timing advance only based on the uplink target. It is an absolute value that is not used in association with the reference timing advance value of the reference cell by the step of aligning the time of the cell. Alternatively, the target timing advance is a relative value used in association with the reference timing advance value of the reference cell in the step of aligning the time of the uplink target cell based on the reference timing advance.

  According to an advantageous embodiment of the invention that can be used additionally or alternatively to the above, the reference cell is a primary cell or one of a plurality of secondary cells, and the target cell is , One of a plurality of secondary cells.

  According to an advantageous embodiment of the invention that may be used additionally or alternatively to the above, the target cell is one of a plurality of target cells forming a group. The time alignment step is performed for each target cell in the group based on the same target timing advance received from the aggregation access point.

  According to an advantageous embodiment of the invention that can be used additionally or alternatively to the above, the mobile terminal is composed of a plurality of non-timed target cells, as described above in the method. A step is performed for each of the target cells.

  According to an advantageous embodiment of the invention, which can be used additionally or alternatively to the above, the measurement results are preferably all configured target cells or configured and all activated targets. Sent to the aggregation access point in one message for the cell.

  The present invention further provides a mobile terminal for aligning uplink transmission times in a mobile communication system. The mobile terminal communicates with the aggregation access point and is configured with an uplink reference cell having a uniform time and an uplink target cell having a non-timed. The processor of the mobile terminal measures transmission and / or reception time difference information for transmissions on the target cell and / or reference cell. The transmitter of the mobile terminal transmits the measurement result to the aggregation access point. The mobile terminal receiver receives the target timing advance from the aggregation access point. The processor and transmitter align the time of the uplink target cell by adjusting timing for uplink transmission on the uplink target cell based on the target timing advance received from the aggregation access point.

  According to an advantageous embodiment of the invention, which can be used additionally or alternatively to the above, the receiver, processor and transmitter can access the random access together with the aggregation access point on the reference cell. Align the time of the reference cell by executing the procedure.

According to an advantageous embodiment of the invention, which may be used additionally or alternatively to the above, the processor starts the first downlink subframe ( _{TDL_RX_SCell} ) and the reference on the target cell. Difference in downlink reception time between the target cell and the reference cell (Δ _Scell-PCell Rx _DL ) by measuring the time between the start of the corresponding downlink subframe on the cell (T _{DL_RX_PCell} ) To decide. The downlink subframes on the reference cell and the target cell point to the same subframe number. Optionally, the transmitter transmits the downlink reception time difference between the target cell and the reference cell as a measurement result to the aggregation access point.

According to an advantageous embodiment of the invention, which may be used additionally or alternatively to the above, the time at which the mobile terminal transmitted an uplink radio frame on the reference cell (T _{UL_TX_PCell} ) And the time difference (Δ _Scell-PCell ) between the target cell and the reference cell by measuring the time difference between the mobile terminal and the time when the mobile terminal received the downlink radio frame on the target cell (T _{DL_RX_SCell} ). Rx _DL -Tx _UL ). The uplink radio frame and the downlink radio frame are related to the same radio frame. Optionally, the transmitter is adapted to transmit the difference in received transmission time between the target cell and the reference cell as a measurement result to the aggregation access point.

  According to an advantageous embodiment of the invention, which may be used additionally or alternatively to the above, the processor and transmitter, when aligning the time of the uplink target cell, The uplink radio frame transmission settings above are respectively the target timing determined by the aggregation access point considered to be associated with the beginning of the downlink radio frame received via the downlink target cell. The advance is used to set the transmission of the uplink radio frame on the uplink target cell relative to the start of the downlink radio frame received via the downlink target cell. Alternatively, when the processor and transmitter align the time of the uplink target cell, the configuration of uplink radio frame transmission on the uplink target cell is received via the downlink reference cell. The transmission of the uplink radio frame on the uplink target cell using the target timing advance determined by the aggregation access point considered to be related to the beginning of the link radio frame, the downlink reference Set in relation to the beginning of the downlink radio frame received via the cell. Alternatively, when the processor and transmitter align the time of the uplink target cell, the configuration of uplink radio frame transmission on the uplink target cell is transmitted via the uplink reference cell. The transmission of the uplink radio frame on the uplink target cell using the target timing advance determined by the aggregation access point considered to be related to the beginning of the link radio frame, the uplink reference Set in relation to the beginning of the uplink radio frame transmitted over the cell.

  According to an advantageous embodiment of the invention, which may be used additionally or alternatively to the above, the transmitter transmits the measurement results on the physical cell's physical uplink shared channel PUSCH to the aggregation access.・ Send to point. Preferably, the measurement result is sent to the aggregation access point is part of the radio resource control layer RRC or medium access control layer MAC, and if it is part of the MAC layer, the measurement result is preferably , Transmitted in the MAC control element.

According to an advantageous embodiment of the invention, which can be used additionally or alternatively to the above, the processor comprises:
● Periodically and / or ● i. Configuration and / or activation of the target cell,
ii. The measurement result exceeds a predetermined threshold,
iii. Timing advance timer expires,
iv. Receiving a request for a measurement report from an aggregation access point;
Triggered to perform measurement of time difference information by a predetermined event such as.

  According to an advantageous embodiment of the invention that may be used additionally or alternatively to the above, the receiver uses the downlink shared channel to target timing within the medium access control MAC control element.・ Receive advance.

  According to an advantageous embodiment of the invention which may be used additionally or alternatively to the above, the target cell is one of a plurality of target cells forming a group, the transmitter and The processor aligns the time of each target cell in the group based on the same target timing advance received from the aggregation access point.

  According to an advantageous embodiment of the invention that can be used additionally or alternatively to the above, the mobile terminal is composed of a plurality of non-timed target cells, the mobile terminal A step according to one of the described methods is performed for each of the target cells.

  According to an advantageous embodiment of the invention that can be used additionally or alternatively to the above, the transmitter is preferably activated with the measurement results, preferably all configured target cells or configurations. To the aggregation access point in one message for all target cells.

  The present invention further provides an aggregation access point for providing timing advance to a mobile terminal in a mobile communication system. The mobile terminal communicates with the aggregation access point and is configured with an uplink reference cell having a uniform time and an uplink target cell having a non-timed. The receiver of the aggregation access point transmits the measurement result from the mobile terminal, and the measurement result indicates transmission and / or reception time difference information related to the transmission on the target cell and / or the reference cell. The aggregation access point processor determines a target timing advance based at least on the received measurement results and the reference timing advance used for uplink transmission on the timed reference cell. . The transmitter of the aggregation access point transmits the target timing advance to the mobile terminal.

According to an advantageous embodiment of the invention, which may be used additionally or alternatively to the above, the receiver starts the first downlink subframe (T _{DL_RX_SCell} ) on the target cell and _Measure the downlink reception time difference (Δ _Scell-PCell Rx _DL ) between the target cell and the reference cell, which is the time between the start of the corresponding downlink subframe (T _{DL_RX_PCell} ) on the reference cell As a result, the downlink subframe on the reference cell and the target cell points to the same subframe number, or the receiver transmits the uplink radio frame on the reference cell (T _{UL_TX_PCell} ) And the time when the mobile terminal receives the downlink radio frame on the target cell (T _{DL — RX_SCell} ) is received as a measurement result (Δ _{Scell−PCell} Rx _DL −Tx _UL ), which is a time difference between the target cell and the reference cell, and the uplink radio frame and the downlink Radio frames are related to the same radio frame.

According to an advantageous embodiment of the invention, which may be used additionally or alternatively to the above, if the receiver receives the difference in the reception transmission time as a measurement result, the processor By subtracting the difference in reception transmission time from the timing advance, the difference in downlink reception time (Δ _Scell-PCell Rx _DL ) between the target cell and the reference cell is determined.

According to an advantageous embodiment of the invention that may be used additionally or alternatively to the above, the processor is based on the difference in downlink reception times and preferably between the target cell and the reference cell. Further, the target timing advance is determined based on the difference in downlink transmission time (Δ _Scell-PCell Tx _DL ). The difference in downlink transmission time between the target cell and the reference cell is the start of the downlink subframe on the reference cell (T _{DL_TX_PCell} ) and the start of the corresponding downlink subframe on the target cell (T _{DL_TX_SCell} ). The downlink subframe refers to the same subframe number.

According to an advantageous embodiment of the invention that may be used additionally or alternatively to the above, the transmitter sends a request for a measurement report to the mobile terminal. The measurement report request is
A deactivation / activation command for deactivating / activating a configured cell, including a flag indicating a request for measurement report, where the flag is a reserved bit of the deactivation / activation command Deactivation / activation command, preferably set to one of the following: ● Radio resource control connection reconfiguration message containing a flag indicating a request for measurement report, or ● Random access channel RACH instruction A random access channel RACH command message having a predetermined code point or a predetermined combination of code points indicating a request for a measurement report.

  The present invention further provides a computer readable medium that, when executed by a processor of a mobile terminal, stores instructions for aligning uplink transmission times in a mobile communication system as follows: Transmission and / or reception time difference information associated with transmissions on the target cell and / or reference cell is measured. The measurement result is transmitted to the aggregation access point. A target timing advance is received from the aggregation access point. The uplink target cell is timed by adjusting the timing for uplink transmission on the uplink target cell based on the target timing advance received from the aggregation access point.

  The computer readable medium stores instructions that, when executed by a processor of the mobile terminal, cause the mobile terminal to perform the method steps described above.

  According to a fifth aspect, the present invention enables reporting downlink timing for an aggregated downlink serving cell as a time difference between a reference cell and at least one target cell. . It is assumed that one of the downlink serving cells configured by the mobile terminal is used as a reference cell for reporting downlink timing. For example, the PCell can be used as a reference cell by a mobile terminal, but another serving cell can be used, for example, the closest of the SCells.

  More particularly, the reporting procedure is based on the mobile terminal measuring the downlink timing for the aggregated downlink serving cell. In particular, the mobile terminal measures transmission and / or reception time difference information related to transmissions on the target cell and / or reference cell. The specific measured time difference information is such that it can be used to estimate the difference in reception time between the reference cell and the target cell.

  Thereafter, the measurement time difference information is compared with a predefined maximum value. In particular, for mobile terminals, it has been found advantageous to specify a predefined maximum value in order to limit the propagation delay time difference for downlink transmissions on the aggregated serving cell. For example, a predefined maximum propagation delay difference can be specified to ensure that the mobile terminal can successfully decode downlink transmissions on the aggregated downlink serving cell.

  According to this aspect of the invention, the comparison is performed by the mobile terminal and then responds to the mobile terminal sending information about the comparison to the aggregation access point or receiving a measurement result from the mobile terminal. Either by the aggregation access point. Advantageously, in both cases, the aggregation access point is provided with information about the downlink timing for the serving cell aggregated by the mobile terminal and the downlink on the aggregated serving cell. Allows the aggregation access point to determine if the transmission can be successfully decoded by the mobile terminal.

  The present invention provides a method for reporting on downlink timing by a mobile terminal in a mobile communication system. The mobile terminal communicates with the aggregation access point and is configured with uplink and downlink reference cells and at least one downlink target cell. The mobile terminal measures transmission and / or reception time difference information related to transmissions on the target cell and / or reference cell. Thereafter, a comparison between the measurement results and a predefined maximum propagation delay time difference for the mobile terminal is performed by the mobile terminal or the aggregation access point. If the mobile terminal compares the measurement result with a predefined maximum propagation delay difference for the mobile terminal, the mobile terminal then transmits information about the comparison result to the aggregation access point. Alternatively, if the aggregation access point compares the measurement result with a predefined maximum propagation delay difference for the mobile terminal, it responds to the mobile terminal sending the measurement result to the aggregation access point. The comparison is performed.

According to an advantageous embodiment of the invention, which may be used additionally or alternatively to the above content, the step of measuring by the mobile terminal is the beginning of the first downlink subframe on the target cell. by measuring the time difference between the reception _{(T DL_RX_SCell)} and the beginning of the reception of the subframe of corresponding downlink on the reference cell _{(T DL_RX_PCell),} the reception time of the downlink between the target cell and the reference cell _{Determining a} difference (Δ _Scell-PCell Rx _DL ) by the mobile terminal, and corresponding downlink subframes on the reference cell and the target cell refer to the same subframe number.

According to an advantageous embodiment of the invention, which may be used additionally or alternatively to the above, the step of measuring by the mobile terminal is that the mobile terminal has transmitted an uplink radio frame on the reference cell by the time _{(T UL_TX_PCell)} the mobile terminal measures the time difference between the time upon receipt of a radio frame of the downlink on the target cell _{(T DL_RX_SCell),} the difference between the received transmission time between the target cell and the reference cell The method further includes determining (Δ _Scell-PCell Rx _DL -Tx _UL ) by the mobile terminal, wherein the uplink radio frame and the downlink radio frame are related to the same radio frame.

  According to an advantageous embodiment of the invention, which can be used additionally or alternatively to the above, the predefined maximum propagation delay time difference is determined for the corresponding downlink on the reference cell and the target cell. Based on the receiver window of the mobile terminal for receiving subframes.

According to an advantageous embodiment of the invention, which may be used additionally or alternatively to the above, the time difference information is measured by the mobile terminal and the information on the comparison result and / or the measurement result is aggregated by the mobile terminal. The steps to send to the access point are
● Periodically executed and / or ● i. Configuration and / or activation of the target cell,
ii. The measurement result exceeds a predetermined threshold, or iii. Receiving reports requests from aggregation access points,
Triggered by a predetermined event such as

According to an advantageous embodiment of the invention that can be used additionally or alternatively to the above, the request for a report from the aggregation access point is:
Deactivation / activation command to deactivate / activate a configured cell, including a flag indicating a report request for transmission and / or reception timing, where the flag is deactivated / active Radio resource control, including a deactivation / activation command, preferably a flag indicating a request for a report on transmission and / or reception timing, preferably set to one of the reserved bits of the activation command A connection reconfiguration message, a random access channel RACH command message, or Random a A Seth channel RACH instruction message.

According to an advantageous embodiment of the invention, which may be used additionally or alternatively to the above, if the step of comparing is performed by a mobile terminal, the step of transmitting information on the comparison result by the mobile terminal Is
O The external maximum propagation delay time difference value, which indicates that the measured time difference exceeded the predefined maximum propagation delay time difference for the corresponding uplink and downlink radio frames or for the corresponding downlink subframes (Outside-maximum-propagation-delay-time-difference value) and, optionally,
O Transmitting the measured time difference information.

  According to an advantageous embodiment of the invention, which may be used additionally or alternatively to the above, the external maximum propagation delay time difference value is determined as a predefined channel state information CSI value or in advance. A defined power headroom report PHR value is transmitted by the mobile terminal via an uplink target cell associated with at least one downlink target cell.

  According to an advantageous embodiment of the invention, which may be used additionally or alternatively to the above, if the comparing step is performed by the aggregation access point, the measurement result is transmitted by the mobile terminal The step includes transmitting the measurement result within a medium access control MAC control element, preferably the step of transmitting the measurement uses a medium access control layer.

  According to an advantageous embodiment of the invention, which can be used additionally or alternatively to the above, according to the mobile terminal if the comparison step is performed by an aggregation access point and / or mobile terminal Transmitting the result includes transmitting the measurement result in a radio resource control RRC message, and preferably transmitting the measurement uses a radio resource control layer.

  According to an advantageous embodiment of the invention that can be used additionally or alternatively to the above, the reference cell is a primary cell or one of a plurality of secondary cells, and the target cell is , One of a plurality of secondary cells.

  According to an advantageous embodiment of the invention, which can be used additionally or alternatively to the above, a mobile terminal is configured with a plurality of downlink target cells, according to claims 1 to 11 The method steps are performed for each of the target cells.

  According to an advantageous embodiment of the invention, which can be used additionally or alternatively to the above, information on measurement results or comparison results is preferably configured for each of the target cells. Sent to the aggregation access point in one message for the secondary cell.

According to an advantageous embodiment of the invention, which can be used additionally or alternatively to the above, according to an advantageous embodiment of the invention, the aggregated access point has a pre-defined maximum for the mobile terminal with the measured time difference information. When information on the comparison result indicating that the propagation delay time difference has been exceeded or when the aggregation access point performs a comparison step and the measured time difference information is a predefined maximum propagation delay for the mobile terminal If it detects that the time difference has been exceeded, the aggregation access point
O sending a deactivation message to the mobile terminal to deactivate the target cell at the mobile terminal, or o the downlink transmission time difference between the target cell and the reference cell as measured by the mobile terminal. Aligning the time of the downlink target cell so that it no longer exceeds the predefined maximum propagation delay difference for the mobile terminal,
The difference in downlink transmission time between the target cell and the reference cell is the start of the downlink subframe on the reference cell (T _{DL_TX_PCell} ) and the start of the corresponding downlink subframe on the target cell (T _{DL_TX_SCell} ). The downlink subframe refers to the same subframe number,
Perform further steps.

  The present invention further provides a mobile terminal for reporting on downlink timing in a mobile communication system. The mobile terminal communicates with the aggregation access point and is configured with uplink and downlink reference cells and at least one downlink target cell. The memory of the mobile terminal stores a predefined maximum propagation delay time difference for the mobile terminal. The processor of the mobile terminal measures transmission and / or reception time difference information related to transmissions on the target cell and / or reference cell and compares the measurement result with a predefined maximum propagation delay time difference for the mobile terminal. The transmitter of the mobile terminal transmits information regarding the comparison result to the aggregation access point.

According to an advantageous embodiment of the invention, which may be used additionally or alternatively to the above, the mobile terminal processor receives the beginning of the first downlink subframe on the target cell ( by measuring the time difference between the T _{DL_RX_SCell)} and the beginning of the reception of the subframe of corresponding downlink on the reference cell _{(T DL_RX_PCell),} the difference between the reception time of the downlink between the target cell and the reference cell ( Δ _Scell-PCell Rx _DL ), and the corresponding downlink subframes on the reference and target cells point to the same subframe number.

According to an advantageous embodiment of the invention, which may be used additionally or alternatively to the above, the mobile terminal processor transmits the time at which the mobile terminal transmitted an uplink radio frame on the reference cell ( by T _{UL_TX_PCell)} the mobile terminal measures the time difference between the time of receiving a radio frame of the downlink on the target cell _{(T DL_RX_SCell),} the difference between the received transmission time between the target cell and the reference cell (delta _Scell-PCell Rx _DL -Tx _UL ) is determined by the mobile terminal, and the uplink radio frame and the downlink radio frame are related to the same radio frame.

  According to an advantageous embodiment of the invention, which can be used additionally or alternatively to the above, the predefined maximum propagation delay time difference is determined for the corresponding downlink on the reference cell and the target cell. Based on the receiver window of the mobile terminal for receiving subframes.

According to an advantageous embodiment of the invention, which may be used additionally or alternatively to the above, the mobile terminal processor measures the time difference information and the transmitter
● Periodically and / or ● iv. Configuration and / or activation of the target cell,
v. The measurement result exceeds a predetermined threshold, or vi. Receiving reports requests from aggregation access points,
Triggered by a predetermined event such as
The measurement result by the mobile terminal is transmitted to the aggregation access point.

According to an advantageous embodiment of the invention that may be used additionally or alternatively to the above, the mobile terminal transmitter comprises:
O The external maximum propagation delay time difference value, which indicates that the measured time difference exceeded the predefined maximum propagation delay time difference for the corresponding uplink and downlink radio frames or for the corresponding downlink subframes And optionally,
○ Send information about the comparison results including the measured time difference information.

  According to an advantageous embodiment of the invention, which may be used additionally or alternatively to the above, the external maximum propagation delay time difference value is determined as a predefined channel state information CSI value or in advance. The defined power headroom report PHR value is transmitted via an uplink target cell associated with at least one downlink target cell.

  According to an advantageous embodiment of the invention that can be used additionally or alternatively to the above, the reference cell is a primary cell or one of a plurality of secondary cells, and the target cell is , One of a plurality of secondary cells.

  According to an advantageous embodiment of the invention, which can be used additionally or alternatively to the above, the mobile terminal is composed of a plurality of downlink target cells, measuring time difference information, measuring results and Comparison with a predefined maximum propagation delay difference and transmission of information regarding the comparison result to the aggregation access point is performed for each of the target cells.

  According to an advantageous embodiment of the invention, which can be used additionally or alternatively to the above, information on measurement results or comparison results is preferably configured for each of the target cells. Sent to the aggregation access point in one message for the secondary cell.

  The present invention further provides an aggregation access point for controlling downlink timing of a mobile terminal in a mobile communication system. The mobile terminal communicates with the aggregation access point and is configured with uplink and downlink reference cells and at least one downlink target cell. The memory of the aggregation access point stores a predefined maximum propagation delay time difference for the mobile terminal. The receiver of the aggregation access point receives measurement results of measurements performed by the mobile terminal measuring transmission and / or reception time difference information related to transmissions on the target cell and / or reference cell from the mobile terminal . The aggregation access point processor compares the measurement result with a predefined maximum propagation delay difference for the mobile terminal.

  According to an advantageous embodiment of the invention that can be used additionally or alternatively to the above, the predefined maximum propagation delay time difference is based on the receiver window of the mobile terminal.

According to an advantageous embodiment of the invention, which can be used additionally or alternatively to the above, the transmitter of the aggregation access point sends a report request to the mobile terminal and the report request Is
Deactivation / activation command to deactivate / activate a configured cell, including a flag indicating a report request for transmission and / or reception timing, where the flag is deactivated / active Radio resource control, including a deactivation / activation command, preferably a flag indicating a request for a report on transmission and / or reception timing, preferably set to one of the reserved bits of the activation command A connection reconfiguration message, a random access channel RACH command message, or Random a A Seth channel RACH instruction message.

  According to an advantageous embodiment of the invention that may be used additionally or alternatively to the above, the receiver of the aggregation access point uses the measurement results, preferably using the medium access control layer Received in a medium access control MAC control element, or preferably in a radio resource control RRC message, transmitted using a radio resource control layer.

  According to an advantageous embodiment of the invention, which can be used additionally or alternatively to the above, the transmitter of the aggregation access point has a predefined measurement result for the mobile terminal. If the comparison result indicates that the maximum propagation delay time difference has been exceeded, a deactivation message for deactivating the target cell in the mobile terminal is transmitted to the mobile terminal.

  According to an advantageous embodiment of the invention, which can be used additionally or alternatively to the above, the transmitter of the aggregation access point has a predefined measurement result for the mobile terminal. If the comparison results show that the maximum propagation delay time difference is exceeded, the downlink time difference is measured so that the time difference measured by the mobile terminal no longer exceeds the predefined maximum propagation delay time difference for the mobile terminal. Align the time of the target cell.

  The present invention further provides a computer readable medium for storing instructions that, when executed by a processor of a mobile terminal, cause the mobile terminal to report on downlink timing in a mobile communication system as follows. Transmission and / or reception time difference information associated with transmissions on the target cell and / or reference cell is measured. The measurement result is compared with a predefined maximum propagation delay time difference for the mobile terminal. Information regarding the comparison result is transmitted to the aggregation access point.

  The computer readable medium stores instructions that, when executed by a processor of the mobile terminal, cause the mobile terminal to perform the method steps described above.

  In the following, the invention will be described in more detail with reference to the accompanying figures and drawings. In the figures, similar or corresponding details are marked with the same reference numerals.

FIG. 2 illustrates an example architecture of a 3GPP LTE system. FIG. 2 shows an exemplary overview of the overall E-UTRAN architecture of 3GPP LTE. FIG. 3 illustrates exemplary subframe boundaries on a downlink component carrier defined for 3GPP LTE (Release 8/9). FIG. 4 illustrates an exemplary downlink resource grid for downlink slots defined for 3GPP LTE (Release 8/9). FIG. 2 is a diagram illustrating the layer 2 structure of 3GPP LTE-A (Release 10) with carrier aggregation enabled for each of the downlink and uplink. FIG. 2 is a diagram illustrating the layer 2 structure of 3GPP LTE-A (Release 10) with carrier aggregation enabled for each of the downlink and uplink. FIG. 3 shows a RACH procedure defined for 3GPP LTE (Release 8/9) where a conflict may occur. FIG. 3 illustrates a contention-free RACH procedure defined for 3GPP LTE (Release 8/9). FIG. 6 is a diagram illustrating uplink transmission timing misalignment from two mobile terminals received at an eNodeB when uplink timing alignment is not performed. FIG. 9b shows that uplink timing alignment is synchronizing uplink transmissions from two mobile terminals as a result of performing uplink timing transmissions in the scenario described with respect to FIG. 9a. FIG. 6 illustrates uplink component carrier time alignment relative to downlink component carrier with timing advance defined for 3GPP LTE (Release 8/9). FIG. 6 is a diagram illustrating an interruption time during an asynchronous handover and a synchronous handover according to time alignment of a plurality of uplink component carriers, respectively. FIG. 6 is a diagram illustrating an interruption time during an asynchronous handover and a synchronous handover according to time alignment of a plurality of uplink component carriers, respectively. FIG. 6 illustrates the reduction in downtime caused by a synchronized handover when using uplink component carrier time alignment calculations according to one of the various embodiments described herein. FIG. 6 illustrates an example scenario where a user equipment aggregates two radio cells, one radio cell originating from an eNodeB and another radio cell originating from a remote radio head (RRH). FIG. 4 illustrates an example scenario where a user equipment aggregates two radio cells, one radio cell originating from an eNodeB and another radio cell originating from a frequency selective repeater (FSR). An exemplary procedure according to various exemplary embodiments of the present invention that allows a user equipment to determine the correct time alignment for uplink component carriers that do not have time for radio cells other than the reference cell. FIG. An exemplary procedure according to various exemplary embodiments of the present invention that allows a user equipment to determine the correct time alignment for uplink component carriers that do not have time for radio cells other than the reference cell. FIG. An exemplary procedure according to various exemplary embodiments of the present invention that allows a user equipment to determine the correct time alignment for uplink component carriers that do not have time for radio cells other than the reference cell. FIG. FIG. 3 illustrates a subframe structure and transmission of that subframe structure via three component carriers according to one exemplary embodiment of the present invention. 3 illustrates the time alignment of the three uplink transmissions with different timing advance values, such as aligning the time of reception at the aggregation access point of the three uplink transmissions for a single subframe. FIG. FIG. 6 shows a format of an activation / deactivation MAC control element that is a command to activate or deactivate one or more S cells. FIG. 6 is a diagram illustrating a format of an extended power headroom MAC control element when a type 2 PHR is reported. Disadvantages of using transmission of PRACH on component carrier to be timed in uplink, in particular uplink between PRACH on one component carrier and PUSCH / PUCCH on another component carrier It is a figure which shows the difference of timing. FIG. 6 is a signaling diagram illustrating an uplink time alignment procedure according to an embodiment of the present invention. FIG. 2 illustrates a network scenario envisioned for one particular embodiment of the present invention. FIG. 6 is a signaling diagram illustrating an uplink time alignment procedure according to another embodiment of the present invention. FIG. 6 is a timing diagram of transmissions exchanged between a UE and an eNodeB, including uplink transmissions with uplink time alignment according to an embodiment of the present invention. P cell and S cell downlink transmissions are delayed in time, transmissions exchanged between the UE and the eNodeB, including uplink timed uplink transmissions according to another embodiment of the invention. It is a timing diagram. 5 is a flow diagram illustrating an uplink time alignment procedure according to a further embodiment of the present invention. It is a figure which shows the format of the MAC control element for transmitting the measurement result which is a difference of the reception time of the downlink between P cell and all the S cells from a mobile terminal to eNodeB. It is a figure which shows the format of the MAC control element for transmitting the measurement result which is the difference of the reception transmission time between P cell and all the S cells from a mobile terminal to eNodeB. In accordance with an embodiment of the present invention, the uplink execution performed at the mobile terminal when the timing advance command received from the eNodeB is calculated relative to the start of the P-cell uplink radio frame. It is a figure which shows a time alignment process. In accordance with an embodiment of the present invention, an uplink execution performed at a mobile terminal when a timing advance command received from an eNodeB is calculated relative to the start of a P-cell downlink radio frame. It is a figure which shows a time alignment process. FIG. 5 is a diagram illustrating a format of a timing advance command according to an embodiment of the present invention. FIG. 4 is a signaling diagram illustrating an uplink time alignment procedure according to one embodiment of the invention. FIG. 6 is a signaling diagram illustrating an uplink time alignment procedure according to another embodiment of the present invention. FIG. 4 is a signaling diagram illustrating a downlink timing reporting procedure according to one embodiment of the invention. FIG. 2 illustrates an example network scenario. FIG. 3 illustrates an exemplary solution for triggering aperiodic CQI reports from user equipment in 3GPP LTE-A (Release 10) system. FIG. 3 illustrates an exemplary solution for triggering aperiodic CQI reports from user equipment in 3GPP LTE-A (Release 10) system. FIG. 6 shows a format of a MAC control element for reporting power headroom for a component carrier. FIG. 4 illustrates an example scenario for a UE's transmit power state and corresponding power headroom resulting in positive and negative power headroom.

  The following paragraphs describe various embodiments of the invention. For illustrative purposes only, most of the embodiments are orthogonal single carrier up with 3GPP LTE (Release 8/9) and LTE-A (Release 10) mobile communication systems discussed in the “Background” section above. The main points will be explained in relation to the link radio access system. The present invention may be advantageously used in mobile communication systems such as, for example, the 3GPP LTE (Release 8/9) and LTE-A (Release 10) communication systems described in the “Background” section above. Note that the invention is not limited to its use in this particular exemplary communication network. The present invention can be widely used in communication systems where time alignment of uplink transmissions on multiple carriers (with different propagation delays) is desired.

  The description given in the “Background” section above provides a more detailed description of exemplary embodiments specific to 3GPP LTE (Release 8/9) and LTE-A (Release 10) described herein. It is intended to be understood and should not be construed as limiting the invention to the particular implementation described of its processes and functions in the mobile communications network.

  One aspect of the present invention is that the time of the uplink component carrier where the time of the radio cell is not aligned relative to the reference cell where the (reference) uplink component carrier is already aligned. It is to align. Timing advance for time alignment of uplink component carriers where radio cells are not aligned with time advance for reference cell uplink component carriers, and time advance for reference cells and time are not aligned It is determined based on the time difference (or the difference in propagation delay) of the reception time of the corresponding downlink transmission by the downlink component carrier of the radio cell including the link component carrier. The time alignment mechanism may be newly configured or activated by the mobile terminal, or may require re-establishment of time alignment (eg, after losing time alignment). Can be used for timed transmissions on component carriers. As will be explained below, the new configuration of the uplink component carrier is, for example, the handover of the mobile terminal to the handover destination access point, or the configuration or active of the further uplink component carrier at the mobile terminal. May result from the operation.

  Corresponding downlink transmissions are simultaneously transmitted by the access point, for example, via the reference cell's downlink component carrier and via the radio cell containing the uplink component carrier that is not in time Represents a transmission (eg, transmission of a given subframe transmitted over those two downlink component carriers). In this case, the difference in the reception time is the propagation component of the transmission transmitted through the downlink component carrier of the reference cell and the downlink component of the radio cell including the uplink component carrier that is not aligned. It is also the time difference (hereinafter also referred to as “propagation delay difference”) from the propagation delay of transmissions transmitted via the carrier. Therefore, in this case, the determination of the timing advance for the time alignment of the uplink component carrier in which the radio cells are not aligned is the timing advance for the reference cell (uplink component carrier), and And a difference in propagation delay of downlink transmissions by downlink component carriers of a wireless cell including a reference cell and non-timed uplink component carriers.

  For the purpose of time alignment, it is not necessary—strictly speaking—for the reference cell to be composed of uplink component carriers. There is a downlink component carrier that is given a reference timing advance value to be used by the mobile terminal and that is received through the reference cell. It is sufficient if the difference in reception time (or difference in propagation delay) can be determined based on them to align the time of other radio cells. However, for most practical implementations, it may be advantageous for the reference cell to be composed of downlink component carriers and (time-aligned) uplink component carriers.

Further, in one embodiment of the present invention, the reference cell to which the timing of the uplink component carrier (s) that are not aligned in time is relatively aligned is the user equipment and the aggregation access point. Is a radio cell including uplink component carriers with time aligned between. However, the reference cell may also be a wireless cell that includes uplink component carriers that are time aligned between the user equipment and an access point different from the aggregation access point. The term aggregation access point (eg, base station or eNodeB) refers to a location in an access network, ie, a node, where uplink transmissions of user equipment on different uplink component carriers are aggregated Used for. What is aggregation?
-Joint physical layer processing by the aggregation access point (eg, including use of one IFFT (inverse fast Fourier transform) for processing of received subframes in an OFDM system, for example) On different uplink component carriers from user equipment for joint demodulation and / or joint decoding of the encoded transport block (s), etc. (for example, joint decoding) That is, simultaneous reception of radio signals corresponding to transmissions on the physical layer (eg, each subframe),
And / or-refers to the processing of protocol data units received in transmissions (eg, respective subframes) on different uplink component carriers from user equipment at the aggregation access point protocol entity. .

  The joint processing of protocol data units received in transmissions on different uplink component carriers from user equipment is in one exemplary implementation-for example for PDU reordering The PDUs obtained from transmissions on different uplink component carriers in the MAC or RLC layer of the aggregation access point.

  In other words, in one exemplary embodiment of the present invention, the aggregation access point may have different uplinks from the user equipment for integration processing (eg, demodulation and / or decoding) by the aggregation access point. Represents a network node that should receive a radio signal corresponding to a transmission (eg, each subframe) on the component carrier, ie, the physical layer. In another exemplary embodiment of the present invention, the aggregation access point receives protocol data received in transmissions (eg, respective subframes) over different uplink component carriers from user equipment. Represents a network node that should process the unit. In one exemplary implementation, the aggregation access point is a base station or eNodeB.

  In accordance with this first aspect of the invention, and in accordance with an exemplary embodiment of the invention, a method is provided for time alignment of uplink transmissions by mobile terminals in a mobile communication system. A mobile terminal includes a first radio cell that includes a downlink component carrier and a timed uplink component carrier, and a downlink component carrier and a timed uplink component carrier It consists of a second radio cell. The mobile terminal receives a downlink transmission from the aggregation access point to the mobile terminal via the downlink component carrier of the first radio cell and the downlink component carrier of the second radio cell, respectively. Determine time difference (or difference in propagation delay) and aggregate access point from mobile terminal via uplink component carrier of first radio cell and uplink component carrier of second radio cell A timing advance for uplink transmission on the uplink component carrier timed of the first radio cell so that uplink transmissions transmitted to the same time arrive at the aggregation access point; Judgment Of the second radio cell by adjusting the timing advance for uplink transmission on the uplink component carrier of the second radio cell based on the received reception time difference (or propagation delay difference) Align uplink component carrier time. Thus, the RACH procedure is not required for uplink component carrier time alignment in the second radio cell.

  In the present specification, simultaneously or at the same time point means the same time point with some deviation within the range of μs added / subtracted. For example, the slight difference between uplink propagation delay and downlink propagation delay in a given radio cell and the granularity of the timing advance value is the perfectness of uplink transmission on the uplink component carrier Suggests that there is no good time alignment. In any case, the simultaneous arrival of uplink transmissions is grouped by the aggregation access point at which the uplink transmissions by mobile terminals over different uplink component carriers (with different propagation delays) are received. Guaranteed to be able to be processed. For example, different transmissions of one given subframe on the uplink component carrier allow the aggregation access point to process all transmissions of that subframe together (integrated processing) And are timed so that those different transmissions are received.

  Further, uplink component carrier time alignment configured for mobile terminals is of course applicable when the mobile terminal must time two or more uplink component carriers. Please also note that. Basically, any number of uplink component carriers can be timed by the procedures described herein as long as there is a reference time advance for the uplink component carrier.

  In addition, it should be noted that a single radio cell may include one or more uplink component carriers and one or more downlink component carriers. It may be assumed that in one radio cell, the propagation delays of all uplink and downlink component carriers are the same. Accordingly, the uplink component carriers of a radio cell may be considered to suffer the same propagation delay and form a group of uplink component carriers that can be associated with a single timing advance value. Of course, if the propagation delays of uplink component carriers are different from one another in the radio cell (eg, by using FSR), a timing advance value for each exposed propagation delay should be given.

  Another second aspect of the invention is to propose a procedure for time alignment of uplink component carriers for use in a mobile terminal handover procedure. Procedures for synchronous and asynchronous handover are provided. The time alignment procedure discussed above can also be used to time uplink component carriers in a radio cell controlled by a handover destination (aggregation) access point to which a mobile terminal is handed over. According to this aspect, a timing advance for one of the uplink component carriers in the radio cell (ie, reference cell) of the handover destination (aggregation) access point can be provided to the mobile terminal (synchronized) Handover) or can be determined by the mobile terminal, for example by performing a random access procedure (asynchronous handover). The other uplink component carrier (s) of the other radio cell (s) to be used by the mobile terminal is then the reference cell as previously described herein. Can be relatively time aligned.

  If a mobile terminal, also referred to as user equipment in 3GPP terminology, aggregates component carriers originating from sources of different bands and physical locations, due to different propagation conditions, these component carriers are All can have different propagation delays.

  Given that an aggregation access point (eg, eNodeB) is handling uplink transmissions over all configured component carriers of a given mobile terminal, the uplink access from the mobile terminal Transmissions should arrive at the aggregation access point simultaneously (at the same time) even though the propagation delays on the component carriers are different. Thus, the aggregation access point may configure the mobile terminal with different timing advance for that uplink component carrier depending on the propagation delay specific to each uplink component carrier. Propagation delay is likely to be the same for component carriers that are in the same frequency band and terminated at the same location (ie, by one access point). Therefore, it is preferable to group a specific component carrier into a timing advance group, and all the component carriers to which a given group belongs are transmitted on the uplink using the same timing advance specific to this group There is a possibility.

  For example, when considering the latest 3GPP communication system, setting several timing advance for one user equipment means that there are several RACH procedures, one RACH procedure for each timing advance group. Suggest that it needs to be implemented. Thus, the eNodeB may determine the propagation delay for each component carrier group in the uplink based on the RACH preambles 701, 802, and is then required using the random access response messages 702, 803 Appropriate timing advance is set for each component carrier group (see FIGS. 7 and 8). This implies a large delay caused by performing several RACH procedures, assuming that the user equipment can only perform a single RACH procedure at a time.

  Similarly, when performing a handover, the user equipment needs to acquire a timing advance value for the component carrier in the handover destination cell through the RACH procedure, which means that the UE cannot send or receive data, “RRC connection It means that there is an increased interruption time between the “reconfiguration” message and the “RRC connection reconfiguration complete” message. FIG. 10 illustrates the steps in a normal asynchronous handover of the user equipment from the handover source eNodeB to the handover destination eNodeB. After the user equipment receives the RRC connection reconfiguration message from the handover source eNodeB, the user equipment first synchronizes the downlink in the handover destination primary cell (P cell) and performs a random access procedure (RACH procedure). Performing, thereby providing time alignment of the uplink component carrier (s) of the primary cell. Further, when the user equipment is configured with further component carriers (in this example, component carriers of two component carrier groups (CoCa groups 1 and 2)) by the handover destination eNodeB that suffers different propagation delays , The user equipment needs to perform further RACH procedures (in this example, the RACH procedure for CoCa group 1 and another RACH procedure for CoCa group 2) that cause the handover delay. When all configured uplink carriers have been aligned, the user equipment terminates the asynchronous handover by sending an RRC connection reconfiguration complete message.

  As highlighted in FIG. 11, in the case of a synchronized handover, the user equipment is given a timing advance value for the primary cell of the handover destination eNodeB, which is the RACH for the primary cell (P cell). Makes it possible to avoid the procedure. However, the RACH procedure for uplink component carriers of all other timing advance groups (CoCa groups 1 and 2) still establishes timing advance for each uplink component carrier appropriately. Need to be executed.

  For illustrative purposes, there are aggregation access points in the network and are exposed to different propagation delays (eg, because the signal path is through a frequency selective repeater) (eg, remote radio head, RRH). Suppose that there are at least two component carriers, each from at least two different physical locations. Further assume that the mobile terminal has at least one uplink component carrier timed (ie, the uplink component carrier of the reference cell). The mobile terminal is required for one reference timing advance, i.e. the component carrier (s) that are not in time from the timing advance of the uplink component carrier that is already in time in the reference cell. Timing advance can be derived. Furthermore, it should be noted that this is true for the uplink component carrier and downlink component carrier of a given radio cell as long as the uplink propagation delay is the same as the downlink propagation delay.

  The timing advance for uplink component carriers that do not have a given time for the radio cell is derived from the timing advance (for uplink component carriers) for the reference cell and the downlink component carrier for the reference cell. Received transmission and reception time difference or propagation delay difference of reception of transmission through the downlink component carrier of the radio cell including the uplink component carrier that is not aligned in time.

  In the following, the procedure for determining the timing advance for uplink component carriers that do not have timers according to an exemplary embodiment of the present invention will be referred to a system based on 3GPP for illustrative purposes only. Explained. In the following example, the aggregation access point corresponds to an eNodeB, while additional access points are formed by a remote radio head (RRH) or a frequency selective repeater (FSR).

  For illustration purposes, the uplink and downlink component carriers are assumed to have a slotted structure, i.e., uplink and downlink transmissions are transmitted in subframes. In the downlink, the subframe structure illustrated in FIGS. 3 and 4 may be used, but the present invention is not limited to that subframe structure. Similarly, in the uplink, the subframe structure illustrated in FIGS. 3 and 4 may be used, but the present invention is not limited to that subframe structure. The number of subcarriers (ie, bandwidth) for the uplink component carrier may be different from the number of subcarriers (ie, bandwidth) of the downlink component carrier. Uplink component carriers can have different bandwidths. Similarly, downlink component carriers can have different bandwidths.

  Further, in the uplink, a single subframe is the entire bandwidth (ie, all subcarriers (or subbands) of all uplink component carriers that are aggregated by an access point (eg, eNodeB). )). From the user equipment perspective, a single subframe is the entire bandwidth of all component carriers (ie, all subcarriers (or subbands)) configured by the mobile terminal in the uplink or downlink, respectively. Has spread. Accordingly, data transmitted in one subframe is transmitted as individual transmissions of modulation symbols (eg, OFDM symbols) on each component carrier configured in the uplink or downlink, respectively. Thus, to process a given single subframe transmitted on the downlink or uplink, a mobile terminal (eg, user equipment) or an access point (eg, base station or eNodeB) can be transmitted by the mobile terminal. Must receive all transmissions of subframes on each configured downlink component carrier, or all uplink component carriers received by (aggregation) access points (eg, eNodeB) .

FIG. 18 illustrates a subframe to be transmitted over three component carriers in the uplink. For example, assuming an OFDM-based communication system, a subframe is a set of N _sub-frame consecutive OFDM symbols in the time domain (eg, 12 or 14 OFDM symbols) and in the frequency domain—here 3 It can be defined as a set of subcarriers corresponding to different component carriers. For illustrative purposes, three component carriers CoCa1, CoCa2, and CoCa3 are shown, each including N _CoCa1 , N _CoCa2 , and N _CoCa3 subcarriers. Component carrier subcarriers may also be grouped into individual subbands. Furthermore, strictly speaking, a subframe does not necessarily extend to a continuous region of subcarriers in the frequency domain, and subcarriers having different component carriers may be spaced in the frequency domain. Similarly, the number of subcarriers for an individual component carrier (ie, the bandwidth of those component carriers) may or may not be the same for different component carriers. For example, component carriers CoCa1 and CoCa2 may each be component carriers that provide a bandwidth of 5 MHz, while component carrier CoCa3 has a bandwidth of 10 MHz.

  The modulation symbol of each OFDM symbol placed on the subcarrier of a given component carrier is considered a subframe transmission. Thus, in the example shown in FIG. 18, a single subframe is transmitted with three transmissions on three component carriers CoCa1, CoCa2, and CoCa3.

  In this context, the time alignment of transmissions on the uplink component carrier is determined by the mobile terminal receiving the downlink subframe boundary (eg, the reference cell or uplink component to be timed). It means to shift (in time) the subframe structure of each uplink component carrier relative to the downlink component carrier subframe boundary of the radio cell to which the carrier belongs. The timing advance (value) indicates the temporal shift to be applied relative to the start / timing of the subframe in the reference subframe structure received on the downlink by the mobile terminal. When appropriately configuring the timing advance for uplink component carriers (for different radio cells with different propagation delays and / or for different mobile terminals), the access point must have all uplink subframe boundaries Can be guaranteed to be aligned with respect to other uplink component carriers.

  FIG. 19 illustrates transmission of three consecutive subframes (numbered 1, 2, and 3) over three uplink component carriers (shown in FIG. 18). Since the user equipment UE uses individual timing advance values for the three component carriers CoCa1, CoCa2, and CoCa3 that are assumed to have different propagation delays for illustrative purposes, each single sub Individual transmissions of the frames will be timed with respect to reception of those transmissions at the eNodeB. This facilitates, for example, that an eNodeB physical layer entity can perform a single IFFT operation when processing individual subframes.

In one exemplary embodiment of the present invention, the radio cell (non-timed) uplink component carrier timing advance value TA _AP2 is the reference cell (timed) at the mobile terminal. Based on the known timing advance value TA _AP1 of the uplink component carrier and further on the basis of the difference in reception time (or difference in propagation delay) ΔT _prop , it is calculated as follows:
TA _AP2 = TA _AP1 + 2 · ΔT _prop (Equation 3)

The reference cell's (time aligned) uplink component carrier timing advance value TA _AP1 is obtained, for example, by performing the RACH procedure as outlined above in connection with FIGS. It may have been acquired by the mobile device. Or the timing advance value TA _AP1 may have been calculated in advance by the user equipment as described herein with reference to another reference cell.

Further, in one exemplary implementation, the time alignment of the reference cell and hence the value of TA _AP1 may be (continuously) updated by the reference cell access point. Therefore, when the timing advance of the reference cell is updated, the mobile terminal may also update the timing advance value calculated relative to the timing advance. The timing advance update for the uplink component carrier (s) based on the updated timing advance of the reference cell uplink component carrier is the difference in reception time (or propagation delay difference). Since ΔT _prop can be subject to change, for example, due to movement of the mobile terminal, it can also include a new measurement of this time difference.

  Alternatively, the time alignment update of the reference cell may include timing advance (s) for the uplink component carrier (s) of the other radio cell (s). May not cause a value update. Instead, the aggregation access point (eg, eNodeB) may send an update command regarding the timing advance value of each uplink component carrier or each uplink component carrier group. . The update command may indicate, for example, correction of the currently set timing advance value. The update command may be sent eg by MAC control signaling in the MAC control element multiplexed to eg downlink transmission.

In Equation 3, the timing advance value TA _AP2 is relative (or more strictly speaking) to the reception timing of the downlink component carrier of the radio cell including the uplink component carrier to be timed. It is assumed to define a timing advance (relative to the reception timing at the beginning of the subframe transmitted on the downlink component carrier).

The difference in reception time (or difference in propagation delay) ΔT _prop is
ΔT _prop = T _DL-TCell -T _DL-RCell (Formula 4)
May be assumed to be defined as Here, the T _DL-TCell is detected by the mobile terminal at the beginning of a subframe in a transmission through a target cell (T cell), ie, a radio cell including an uplink component carrier to be timed. Represents a point in time. T _DL-RCell represents a time point at which the start of the same subframe is detected by the mobile terminal in the transmission via the reference cell (R cell).

When the timing advance value TA _AP2 defines the relative timing advance with respect to the reception timing of the downlink component carrier of the reference cell, the timing advance value TA _AP2 is calculated as follows.
TA _AP2 = TA _AP1 + ΔT _prop (Equation 5)

However, defining the timing advance value TA _AP2 as in Equation 5 means that the reference cell is “censored”, ie, the component carrier (s) of the reference cell are not (eg, due to handover). There may be a disadvantage that the mobile terminal may need to recalculate all timing advance values when activated or no longer configured. This is true if the loss of the reference cell (in time alignment) still suggests a loss of time alignment of all other radio cells that are timed relative to that reference cell. However, after initial time alignment relative to the reference cell, the time alignment of individual radio cells (ie, uplink component carriers) is individually or grouped by the aggregation access point. Updated to Thus, the loss of the reference cell may not necessarily require a new time alignment of other radio cells configured by the mobile terminal.

  In the following, the timing advance determination for non-timed uplink component carriers (non-timed radio cells) is outlined in more detail with reference to some exemplary scenarios. In the exemplary scenario shown in FIG. 13, the user equipment originates from two radio cells, a first location, eg, one radio cell originating from eNodeB, and a different location, eg, remote radio head (RRH). Assume that another radio cell is aggregated. An RRH represents a wireless device that is connected to and remote from the access point, such as a base station that controls the RRH (eg, an eNodeB in a 3GPP based system). The interface between the access point and the RRH is, for example, the common public radio interface (CPRI) standard-www. cpri. It is possible to use an info reference. The RRH and the access point that controls it can be connected to each other by, for example, fiber optic cables.

  The transmission over the uplink component carriers of the two radio cells is processed at the same aggregation node, i.e. eNodeB in this example, the downlink component carrier and the uplink component carrier of each radio cell. Have the same propagation delay. A radio cell including an uplink component carrier UL CoCa1 and a downlink component carrier DL CoCa1 between the mobile terminal UE and the eNodeB is denoted as a primary radio cell (eg, a P cell of user equipment). On the other hand, the radio cell including the uplink component carrier UL CoCa2 and the downlink component carrier DL CoCa2 between the mobile terminal UE and the RRH is represented as a secondary radio cell (for example, an S cell of the user equipment). All transmissions transmitted by the user equipment via the secondary cell are received by the RRH transceiver and forwarded to the eNodeB via the interface between the RRH and the eNodeB. Similarly, when transmitting data via RRH, the eNodeB transmits data to the RRH using, for example, the CPRI protocol, and the RRH transmits it to the user equipment via the downlink component carrier of the secondary cell. Transfer data.

  The primary radio cell may be considered as the P cell of the user equipment in this example and is the reference cell for time alignment. However, any other wireless cell that the user equipment has aggregated and is currently in timing can still serve as the reference cell. For example, the time alignment of the uplink component carrier UL CoCa1 of the primary radio cell may have been set by the eNodeB through the RACH procedure performed in the primary radio cell.

  FIG. 15 illustrates a procedure according to an exemplary embodiment of the present invention that allows a user equipment to determine the correct time alignment for uplink component carriers that are out of time for radio cells other than the reference cell. ing. For illustrative purposes, it is assumed that eNodeB is an aggregation access point and RRH serves as an additional access point, as outlined above in connection with FIG. The eNodeB transmits a subframe on the downlink to the user equipment via the primary radio cell and the secondary radio cell, respectively. For illustration purposes, it is assumed that the eNodeB transmits all transmissions (corresponding transmissions) of a single subframe simultaneously. The corresponding transmission of a given subframe is indicated by the same number in FIG. Since transmissions of a given subframe take different propagation paths, each transmission of a given subframe is received at different times at the user equipment, as highlighted in the upper part of FIG.

）、ＲＲＨからユーザ機器に転送される（伝播遅延

）、ＲＲＨを介したサブフレームの送信が原因である。さらに、考慮される必要がある可能性があるＲＲＨにおけるサブフレームの無視できない処理遅延

も、存在し得る。プライマリ・セルを介したｅＮｏｄｅＢからユーザ機器へのサブフレームの送信の伝播遅延は、

と表される。 The time shift between the transmission of subframes by the eNodeB and RRH is forwarded to the RRH by the eNodeB via the interface (propagation delay, for example).

), Transferred from RRH to user equipment (propagation delay)

), Due to the transmission of subframes via RRH. In addition, non-negligible processing delay of subframes in RRH that may need to be considered

Can also exist. The propagation delay of the transmission of subframes from the eNodeB to the user equipment via the primary cell is

It is expressed.

The user equipment measures the time difference ΔT _propo between reception of the corresponding transmission of the subframe. More specifically, the user equipment transmits subframe #i through the downlink component carrier of the radio cell and the downlink component of the reference radio cell, where the uplink component carrier should be timed. Determine the difference between the reception times of the transmission of subframe #i via the carrier. In the example shown in FIG. 15 where the eNodeB primary radio cell is the reference cell for time alignment, the user equipment starts the subframe transmitted over the downlink component carrier of the reference cell. Determine when it is received and at what point the beginning of the exact same subframe via the downlink component carrier of the radio cell of the RRH is received, and the time difference ΔT _{prop of} these two reception times Calculate

と定義され、ここで、項

は省略され得る。ｅＮｏｄｅＢはサブフレームのすべての送信を同時に送信するので、実際は、ΔＴ_ｐｒｏｐは、図１３に示されるように、基準セル（プライマリ無線セル）およびセカンダリ無線セルを介したサブフレームの送信の伝播遅延の差を表す。 The time difference ΔT _propo between reception of corresponding transmissions in the subframe assuming the scenario shown in FIG.

Where

Can be omitted. Since eNodeB transmits all transmissions of subframes simultaneously, in fact, ΔT _prop is the propagation delay of transmission of subframes through the reference cell (primary radio cell) and secondary radio cell, as shown in FIG. Represents the difference.

In order to ensure that the corresponding transmissions arrive at the eNodeB simultaneously when sending corresponding transmissions of subframes through different uplink component carriers that are exposed to different propagation delays, the user equipment shall There is a need to compensate for the delay difference and to further accelerate the transmission (relative to the uplink transmission on the uplink component carrier of the reference cell). Thus, in the exemplary scenario of FIG. 13, the transmission of subframes on the uplink component carrier UL CoCa2 via RRH is performed with reference timing advance TA _eNodeB (known to the user equipment) and user equipment. Should be advanced by twice the time difference ΔT _prop measured by. Thus, the correct timing advance to be applied for uplink transmission of subframes transmitted over RRH is
TA _RRH = TA _eNodeB + 2 · ΔT _prop (Equation 7)
And can be calculated.

As mentioned above, the timing advance value TA _eNodeB of the reference cell / reference uplink component carrier UL CoCa1 may have been known by the user equipment from the RACH procedure with the eNodeB, or another / previous reference It may have been determined as described above based on known timing advance from the cell.

The eNodeB controlling the reference cell in the scenario of FIG. 13 may constantly adjust the time alignment of the uplink component carrier UL CoCa1 by sending a continuous update of the timing advance value TA _eNodeB . Timing advance updates may be transmitted, for example, by MAC signaling, eg, using a MAC control element that is multiplexed into a downlink transmission transmitted to the user equipment.

  In one further exemplary embodiment of the present invention, time alignment of uplink component carriers may be controlled using a timer. A separate timer may be held by the mobile terminal for each timing advance value (each associated with either an individual uplink component carrier or an uplink component carrier group) There is. The mobile terminal resets and starts a timer each time the mobile terminal receives an update command for a given timing advance value (associated with an uplink component carrier or uplink component carrier group, respectively) To do. Whenever the timer expires, i.e., timing alignment is considered lost, the time alignment can be reestablished by the mobile terminal using the mechanisms described herein, e.g., the mobile terminal And the timing advance value can be recalculated based on the received time difference (or propagation delay difference) measurement, or the user equipment can alternatively perform a RACH procedure to Alignment may be re-established.

  Thus, the uplink may be considered timed as long as the user equipment maintains a reference timing alignment on the uplink of another radio cell.

As illustrated in FIG. 16, the timing advance value TA _RRH is on the downlink component carrier by the reference cell, ie, the downlink component carrier DL CoCa1 of the primary radio cell, as shown in FIG. May be calculated relative to the reception timing of the downlink subframe boundary. Therefore, the equation for calculating the timing advance value TA _RRH for the uplink component carrier UL CoCa2 of the secondary radio cell is:
TA _RRH = TA _eNodeB + ΔT _prop (Equation 8)
Where the values TA _eNodeB and ΔT _prop remain unchanged compared to Equation 7.

Further, in the examples of FIGS. 15 and 16, the timing advance values TA _RRH and TA _eNodeB are not only for aligning uplink transmissions on the uplink component carrier with respect to subframe boundaries, It is also selected to align the subframe boundaries between the component carrier and the downlink component carrier. However, this is not essential.

As illustrated in FIG. 17, the timing advance value for the uplink component carrier is selected such that the subframe boundaries in the uplink component carrier and the downlink component carrier are not aligned. There is a possibility. This is because, for example, the reference timing advance value (represented as TA _AP1 or TA _eNodeB in the example above) is the propagation delay between the aggregation access point and the mobile terminal as shown in FIG. This may be realized when configured by an aggregation access point (e.g., eNodeB) so as not to be doubled. At that time, the timing advance value for the uplink component carrier (s) that are not in time is still based on this reference timing advance value as described above in connection with FIGS. It can be determined as outlined. However, then the timing advance value (s) calculated based on such reference timing advance values will still align subframe boundaries on the uplink component carrier, but the uplink・ Subframe boundaries between component carrier and downlink component carrier are not aligned.

  The same assumptions and calculations described above may also be used in scenarios where the radio signal between the mobile terminal and the aggregation access point and vice versa is going through a frequency selective repeater (FSR). FSR may also be referred to as a bi-directional amplifier (BDA). The FSR receives a radio signal by a receiving antenna, amplifies the received radio signal by a signal amplifier, and broadcasts the amplified radio signal through an internal antenna to strengthen the radio signal of the radio system in a local region. It is a device used for. Usually, the operation of FSR is transparent to other network nodes, i.e. access points and mobile terminals. The FSR may be assumed to enhance the radio signal of one or more component carriers of the downlink and uplink. If only a configured subset of component carriers is amplified by the FSR, the radio signals of the different component carriers are exposed to different propagation delays as in the situation already discussed in connection with FIG. there is a possibility.

  One difference in the use of RRH or FSR is the physical layer reception location. The physical layer reception of uplink transmissions for radio cells originating from the location of the aggregation access point (e.g. eNodeB) takes place at the aggregation access point, whereas for radio cells originating from the location of the RRH, The reception of the layer is performed in the RRH. In essence, the time alignment method described above with respect to the scenario shown in FIG. 13 is received at the RRH such that all uplink transmissions of all mobile terminals arrive at the RRH simultaneously. Coordinates the uplink timing for the radio cell and that all uplink transmissions of all mobile terminals arrive at the RRH at the same time is free of interference of all uplink radio signals arriving at the RRH from all mobile terminals Important for reception. In addition, the processing delay in RRH and the propagation delay from RRH to the aggregation access point (eg, eNodeB) may be assumed to be the same for all uplink radio signals received at RRH and are therefore forwarded by RRH. All uplink data arrives at the aggregation access point simultaneously, which is beneficial for further processing at higher layers.

  For the case where a frequency selective repeater is used, all uplink radio signals are received at the location of the aggregation access point (eg, eNodeB). Therefore, it would be advantageous for the physical radio signals of all uplink transmissions for all radio cells to arrive at the same instant to ensure physical layer processing without interference.

  FIG. 14 shows that FSR is used to strengthen secondary radio cell downlink and uplink component carriers (DL / UL CoCa2) while primary radio cell downlink and uplink component carriers (DL The / UL CoCa1) radio signal illustrates a scenario where it is not amplified by the FSR. In this scenario, it is assumed that the uplink and downlink component carriers of the secondary radio cell are enhanced by the FSR, and the user equipment is not receiving the uplink and downlink carriers of the secondary radio cell directly from the eNodeB. The Thus, in this scenario, the propagation delay of uplink and downlink component carriers in the secondary radio cell may still be assumed to be different from the propagation delay of uplink and downlink component carriers in the primary radio cell. . Furthermore, there is no difference in propagation delay between the uplink component carrier and the downlink component carrier in the secondary radio cell.

If it is further assumed that the timing advance value TA _{eNodeB for the} uplink component carrier UL CoCa1 of the primary radio cell is known, then the user equipment shall, as described above, this reference time alignment TA _eNodeB , Of the transmission on the uplink component carrier UL CoCa2 of the secondary radio cell based on the difference in reception time (or the difference in propagation delay) between the transmission of the downlink component carrier of the primary radio cell and the secondary radio cell We can arrange time. Basically, the same equation above can be reused by replacing the term TA _RRH with the term TA _FSR representing the timing advance value for the uplink component carrier UL CoCa2 of the secondary radio cell.

  The use of FSR—because the FRS operates transparently—may be unknown to the mobile terminal, so the aggregation access point (e.g., eNodeB) is the mobile terminal (s) May inform their mobile terminals whether they are allowed to calculate timing advance values based on reference cells. The aggregation access point (e.g., eNodeB) knows the configuration of the network and thus may also know the use and configuration of the FSR (s) near that aggregation access point There is.

Method of configuring timing advance by aggregation access point As already indicated above, a mobile terminal (eg, user equipment) knows the location from which the different radio cell that the mobile terminal is aggregating from. There is no possibility. Thus, in this case, the mobile terminal is also unaware of the actual propagation delay incurred by the mobile terminal's uplink transmission. The mobile terminal may still not know if both the uplink and downlink of the radio cell are transmitted from the same location. Thus, in one further embodiment of the present invention, the method for aligning the time of the uplink component carrier depending on the reference cell is, for example, only if the aggregation access point allows this procedure. May be applied. For example, in a mobile communication system based on 3GPP, the network topology and the exact location of nodes (access points) and the location of transmit and receive antennas are known to the eNodeB. Therefore, only the eNodeB knows whether the uplink transmission of the user equipment is subject to the same propagation delay as the downlink signal received by the user equipment.

  Taking into account the above content for each cell configured with a mobile terminal (eg, user equipment), the aggregation access point (eg, eNodeB) may be configured in, for example, an uplink time alignment configuration mode, ie, this Whether the calculation of timing advance already considered in the specification can be applied to an uplink component carrier or uplink component carrier group, or uplink component carrier or uplink component carrier Signals whether an initial timing advance for the carrier group should be set through the RACH procedure.

  This signaling introduces a flag indicating, for example, whether the RACH procedure should be used to time or whether the mobile terminal can calculate the timing advance based on the reference timing advance Can be realized. The flag may be signaled for each individual radio cell or for a group of radio cells whose component carriers are subject to equal propagation delay.

  Information on how to time the uplink component carriers for a given radio cell should be available at the mobile terminal before transmission and reception on the radio cell can begin. Thus, in one exemplary implementation, the flag for signaling the time alignment configuration mode may be conveyed to the mobile terminal by RRC signaling when the radio cell is configured. For example, signaling information of a flag (for example, 1 bit) for indicating the time alignment configuration mode may be included in a radio resource configuration message of the RRC protocol, for example.

Synchronous and Asynchronous Handover The method described above can also be used in handover scenarios where the mobile terminal will aggregate a new uplink component carrier of one or more handover destination cells. Instead of performing the RACH procedure for the handover destination radio cell, the mobile terminal can uplink the uplink component carrier relative to the reference cell controlled by the handover destination aggregation node (or base station / eNodeB). Time alignment can be determined.

  Once the reference timing advance is established in the handover target radio cell, an additional radio cell composed of a handover destination aggregation access point (eg, eNodeB) for the mobile terminal (eg, user equipment) is added to the further RACH procedure. The time can be aligned without using. Thus, a handover in which the mobile terminal will have several aggregated radio cells under the control of the handover destination aggregation access point is configured for the radio cell of the new handover destination aggregation access point. Instead of using one RACH procedure for every timing advance to be made, the asynchronous handover starts by using only a single RACH procedure.

  The time alignment of the new reference cell under the control of the handover target aggregation access point is as described above (for asynchronous handover) either through the RACH procedure or when using a synchronous handover, the handover source aggregation access By configuring a timing advance value for one of the handover target radio cells through the point (ie, the access point from which the mobile terminal is handed over to the new / handover destination access point, eg, eNodeB) There is a possibility to get either. In the latter case, the RACH procedure may not be required at all in the handover destination cell.

  In one exemplary embodiment of the invention related to a 3GPP based mobile communication network such as 3GPP LTE-A, the handover source eNodeB (acting as an aggregation access point) performs user equipment to The handover is initiated by sending an RRC connection reconfiguration message to the user equipment. The RRC connection reconfiguration message informs the user equipment about a new eNodeB that controls the handover target radio cell to be configured by the user equipment (acting as a new aggregation access point). Furthermore, the RRC connection reconfiguration message indicates a radio cell to be configured by the user equipment. Optionally, ie in the case of a synchronized handover, the RRC connection reconfiguration message sets the timing advance for the uplink component carrier (or uplink component carrier group) under the control of the handover destination eNodeB. In addition, the timing advance value is included.

  For asynchronous handover, the user equipment establishes downlink synchronization of the handover target radio cell and performs the RACH procedure on one of the uplink component carriers to perform this uplink component carrier (or Establish time alignment for the uplink component carrier group to which this uplink component carrier belongs. Once time alignment is established, i.e., when the timing advance value is set, the other uplink component carriers configured by the user equipment are time aligned according to the method outlined herein above. Can be. Thus, for asynchronous handover, the user equipment needs to perform only one RACH procedure, but can time all uplink component carriers.

  If the eNodeB does not allow the timing advance value to be calculated based on the reference cell (eg, via RRC control signaling), the user equipment cannot be configured based on the timing advance value of the reference cell. It may be necessary to perform more than one RACH procedure in order to time the uplink component carriers. For example, the RRC connection reconfiguration message may indicate for which handover target radio cell the user equipment can calculate the timing advance based on the reference cell.

  In the case of synchronized handover, no RACH procedure is required. An initial reference timing advance for the handover target radio cell that serves as a reference is provided to the user equipment by the handover source eNodeB. Then, all remaining radio cells controlled by the handover destination eNodeB are time aligned using the method described above (for example, if the eNodeB allows time alignment of each radio cell based on the reference timing advance). Can be. As shown in FIG. 12, handover delay is minimized. The user equipment establishes the downlink synchronization of one of the handover destination cells (acting as a reference cell) and sets the timing advance as given by the eNodeB in the RRC connection reconfiguration message. At that time, the user equipment only needs to calculate the timing advance value for the other uplink component carrier or component carrier group (s) and then the RRC connection reconfiguration complete A message can be sent back to the new eNodeB to terminate the handover.

  Accordingly, the calculation of timing advance (s) for time alignment of uplink component carriers relative to the reference cell is related to the prior art for both synchronous and asynchronous handovers. Compared to this method, the handover delay can be significantly reduced, and thus the latency and delay associated with this procedure can be reduced.

  Another aspect of the present invention is to aggregate the time of the uplink when the serving cell is not aligned, and to aggregate timing information used to align the time of the uplink when the serving cell is not aligned It is to send to the access point.

  The following specific scenarios are envisaged, but should not be considered as limiting the invention, but as examples to illustrate the principles of the invention. It is assumed that the reference cell is a P cell and the target cell is an S cell. The aggregation access point is assumed to be an eNodeB.

  FIG. 23 illustrates various steps performed by mobile terminals UE and eNodeB to enable a time alignment procedure according to an embodiment of the present invention and messages exchanged between those mobile terminals UE and eNodeB. The signaling diagram shown is disclosed.

  The mobile terminal UE has already configured a P cell in which the mobile terminal UE exchanges data with the eNodeB. The P cell of the mobile terminal UE is already timed in the uplink, i.e., uplink transmissions made by the mobile terminal UE on the P cell are received by the eNodeB in the other transmissions on this cell. It is performed by the mobile terminal UE at a timing that is synchronized with reception of the uplink transmission of the mobile terminal UE. The P-cell is initially configured by performing the RACH procedure as described in the background section, whether the RACH procedure is contention based or non-contention based (see FIGS. 7 and 8). The uplink time was aligned.

  It is theoretically possible to synchronize the P cell first using the principles of the present invention, assuming that the reference is an S cell with a fixed uplink time, but it seems relatively unfavorable. It is. However, in the following description, when the UE aggregates multiple serving cells, the P cell is always uplink synchronized, for example, the PUCCH is transmitted on the P cell. Assume that it is initially synchronized on the uplink using the RACH procedure and has the “best” uplink time alignment (since the RACH procedure is more accurate).

  At this point, the mobile terminal UE is configured using a secondary cell and an S cell, but the S cell is not yet ready in the uplink. For example, an S cell has just been configured, or an S cell that previously had uplink time lost its uplink synchronization (eg, timing advance timer expires) . In any case, the mobile terminal UE must now realize uplink time alignment in order to be able to transmit uplink data to the eNodeB through the S cell. The following steps are performed as illustrated by FIG.

  1. The mobile terminal UE performs measurements to determine specific timing information for transmission / reception in the P cell and / or S cell. As will be explained in more detail below, there are various timing information that can be determined at the mobile terminal UE. The timing information that the terminal measures is the S cell by taking into account the time alignment of the P cell uplink, which timing information is already in time and therefore serves as a reference for the time alignment of the S cell. It is such that it allows the terminal to determine the timing advance for.

  With respect to steps 4a, 4b, or 4c, information on measurements that may be sent to the eNodeB is not yet known to the eNodeB. Therefore, it is related to timing that eNodeB does not know, such as transmission and / or reception timing information of signal exchange performed on P cell and / or S cell between mobile terminal UE and eNodeB. It is important to keep in mind.

  2. The mobile terminal UE determines the timing advance for the S cell using the measurement information. The determination is based on measurement information and information related to P cell uplink time alignment. There are various possibilities of how this can be achieved, and the following description considers those possibilities in more detail.

  Preferably, this timing advance for the S cell is an absolute value applied by the mobile terminal UE to the time of arrival of the downlink transmission from the eNodeB on the S cell, ie the initial timing known from the standard. -Determined by the mobile terminal UE as well as the advance value. Alternatively, the determined timing advance is relative to the timing advance used for the P cell, so the uplink of the uplink to the eNodeB by the mobile terminal UE on the timed P cell It may also allow the mobile terminal UE to apply a value for the transmission time of the transmission or for the arrival time of the downlink transmission from the eNodeB on the P cell.

  For step 4a, 4b, or 4c, the timing advance determined by the mobile terminal UE for uplink transmission on the S cell is determined by the mobile terminal UE performing a RACH procedure on the S cell or on the S cell. It is still unknown to the eNodeB except when it receives a TA command to be applied for uplink transmission.

  Theoretically, the eNodeB determines the timing time by measuring the relative time difference between uplink transmissions on the P and S cells when uplink transmissions are performed on the P and S cells. Advance can be determined. However, such measurements require the UE to transmit with an incorrect timing advance on the S cell that causes interference with other uplink transmissions on the same S cell. Such interference is generally avoided. Apart from unacceptable interference, the measurements are not very accurate. In other words, although there is a theoretical possibility for the eNodeB to measure the timing advance for use by the mobile terminal UE, in practice the measurement of the time difference is an accurate determination of the timing advance on the S cell. Not possible.

  In contrast, time alignment based on random access procedures prevents interference with other uplink transmissions on the S cell. Note that the RACH preamble has some specific characteristics described in the background art section to allow some good detection on the eNodeB side.

  In other words, although there is a theoretical possibility for the eNodeB to measure the timing advance for use by the mobile terminal UE, in practice the measurement of the time difference is an accurate determination of the timing advance on the S cell. Not possible.

  However, the mobile terminal provides measurement information to the eNodeB (as in step 1), so that the eNodeB has a timing advance for the S cell similar to the timing advance for the S cell determined by the mobile terminal UE in step 2. Advances can be calculated. It will be explained later that the measurement and / or timing advance transmitted information about the S cell allows the eNodeB to control the time alignment process in the S cell. For now, the eNodeB can still determine the timing advance for the S cell in the same way as the mobile terminal UE, ie based on the measurement information and the information related to the uplink time alignment of the P cell. It is important to note.

  3. Using the determined timing advance for the S cell, the mobile terminal UE can align the time of the uplink transmission timing of the S cell. How accurately the uplink transmission timing is adjusted depends on the specific type of timing advance determined. If the determined timing advance information is an absolute value of the timing advance to be applied, the mobile terminal UE receives the downlink received on the S cell according to the amount of time indicated by the timing advance information. The uplink transmission timing of the mobile terminal UE is set relative to the start of the subframe. Alternatively, if the timing advance is determined relative to the timing advance of the P cell by the mobile terminal UE, the mobile terminal UE is timed according to the amount of time indicated in the time advance information The uplink transmission timing of the mobile terminal UE is set relative to the start of the uplink subframe transmitted on the P cell or relative to the downlink transmission on the P cell.

  Thus, the mobile terminal UE can align the uplink time of that mobile terminal UE in the S cell and then start sending scheduled uplink transmissions based on the received uplink grant .

  4a, 4b, or 4c. The mobile terminal UE sends information about the measurement of step 1 and / or the timing advance of step 2 to the eNodeB, allowing the eNodeB to better control the timing alignment of the S cell.

  Transmitting the measured and / or determined timing advance information is not necessarily after the mobile terminal UE has applied the determined timing advance to time the uplink transmission on the S cell (ie, , As step 4c). Alternatively, the mobile terminal UE obtains information on the measurement of step 1 immediately after the measurement of that information in step 1 (ie step 4a in FIG. 23) or after decision step 2 (ie step 4b). Or, after time alignment of uplink transmission on the S cell in step 3 (ie, step 4c), there is a possibility to transmit to the eNodeB. According to another alternative method, the mobile terminal may use the determined timing advance of step 2 immediately after the determination of its timing advance in step 2 (ie, step 4b in FIG. 23) or step 3 May be transmitted to the eNodeB after time alignment of uplink transmission on the S cells (ie, step 4c). In general, the timing of timing measurement reports performed by a mobile terminal can vary as will be explained later, whether it is periodic, event-triggered, or requested by an eNodeB There is a possibility that either.

  As already explained, the eNodeB also determines a timing advance for the S cell similar to the timing advance for the S cell determined by the mobile terminal UE in step 2 based on the transmitted information of the measurement in step 4a. Can be determined. When using an eNodeB that can convert between both transmitted information, the alternative method described above may be considered an equivalent alternative for the transmitted information.

  As explained above, there are various advantages provided by the present invention. First, procedures for applying different timing advance for different component carriers, i.e. cells, are performed. Thus, in situations where the propagation of the S cell is different from the P cell, the uplink timing may be adjusted separately for each cell when possible. Furthermore, performing a random access procedure in the S cell may be avoided. Furthermore, avoiding the RACH procedure avoids some problems such as complex prioritization rules for power limiting, or power amplifier problems.

  In addition, the uplink synchronization process according to the present invention is fast compared to when the RACH procedure is performed. As will be shown in detail later, this is particularly important for activation of S-cells that do not have uplink time. In addition, measurement and / or transmission of timing advance value information about the S cell to the eNodeB may cause the eNodeB to track changes in the S cell timing advance, and the eNodeB may uplink in the mobile communication system on the S cell. It is possible to control the alignment of the transmission times.

  In the following, more specific embodiments of the invention will be described with reference to FIGS.

  FIG. 24 shows a scenario where the P cell, S cell 1 and S cell 2 are provided to different UEs by the eNodeB, ie, UE1, UE2, UE3. Secondary serving cell Used by S cell 1 and S cell 2, which amplifies signals transmitted / received on S cell 1 and S cell 2, but does not amplify signals transmitted / received on P cell A frequency selective repeater (FSR) configured for frequency is provided. As shown in FIG. 24, the P cell coverage is wider than the S cell coverage.

The lower part of FIG. 24 shows the difference in downlink reception time (Δ _Scell-PCell Rx _DL ) at the mobile terminal between the S cell 1 or 2 and the P cell with respect to the position of the UE in the cell. It is drawn on the graph. The difference in downlink reception time is the difference between when the UE receives a downlink subframe from the eNodeB on the S cell and when the UE receives the downlink subframe from the eNodeB on the P cell. It is.

  In this particular scenario, the need for different uplink timing advance for P cell, S cell 1 and S cell 2 varies depending on the location of the UE. More specifically, three UEs are shown in FIG. 24, where UE1 is located at A in the coverage of P cell, S cell 1 and S cell 2, and UE2 is S cell 1/1 provided by eNodeB. Located in area B where the coverage for S cell 2 and the coverage for S cell 1 / S cell 2 provided by FSR overlap, UE 3 is outside the coverage for S cell 1 / S cell 2 provided by eNodeB. However, it is located in C which is in the coverage for S cell 1 / S cell 2 provided by FSR.

  From location A to location B, P cell, S cell 1 and S cell 2 are provided to the UE by the same transmitting node, eg eNodeB. Therefore, the propagation delay of the three cells should be substantially the same, and thus the difference in downlink reception time should be negligible. As a result, the same timing advance can be used for P-cell, S-cell 1 and S-cell 2. On the other hand, at location B, the signal for S cell 1 / S cell 2 from the FSR is stronger than the signal for S cell 1 / S cell 2 from the eNodeB, and accordingly, UE 2 at location B It is assumed that a signal is received on the P cell from, and a signal is received on S cell 1 / S cell 2 from the FSR. Therefore, the propagation is different between the P cell signal and the S cell 1 / S cell 2 signal, and this difference results in different downlink reception timings between the P cell and the S cell 1 / S cell 2. As is apparent from the lower part of FIG. 24, the difference in downlink reception time depicted in the graph measured by UE2 between P cell and S cell 1 / S cell 2 is that UE 2 (from eNodeB). A) suddenly change to a specific value at the moment of switching from one receive path to another (from the FSR).

  In this exemplary scenario, at location B, the path length difference between the P cell path and the S cell 1 / S cell 2 path is its maximum, so the downlink reception time difference is also its maximum. is there. The difference in downlink reception time decreases as the UE moves further towards the FSR, and is exactly the minimum at the location of the FSR, and the difference in downlink reception time is mainly related to S cell 1 / S cell 2. FSR time for reception, processing and transmission of amplified signal. When moving away from the FSR, the difference in downlink reception time increases again.

  Therefore, UE2 and UE3 cannot use the same timing advance used for P cells for S cell 1 / S cell 2 and for those S cell 1 / S cell 2 Separate uplink timing advance must be configured. However, in this scenario, the propagation delay for S cell 1 and S cell 2 is the same, so the same timing advance can be used for S cell 1 and S cell 2.

One central idea of the present invention is to determine the timing advance for the S cell relative to the uplink timing of the P cell with the uplink time aligned. In particular, the timing advance used by UE 3 to synchronize uplink transmissions in the S cell is defined in relation to the uplink timing of the P cell with the uplink time aligned. The following timing relationships apply to the timing advance TA _SCell for the S cell in relation to the P cell timing advance TA _PCell and other parameters.
TA _PCell = PD _{UL_PCell} + PD _{DL_PCell} (Formula 7)
_{TA SCell = PD UL_SCell + PD DL_SCell} = PD UL_PCell + PD DL_PCell + (Δ SCell-PCell PD DL + Δ SCell-PCell PD UL)
= TA _PCell + (Δ _SCell-PCell PD _DL + Δ _SCell-PCell PD _UL )
Where Δ _SCell-PCell PD _DL is the difference between the P cell and S cell downlink propagation delays and Δ _SCell-PCell PD _UL is the difference between the P cell and S cell uplink propagation delays. Is the difference.

Δ _SCell PD _UL-DL is the difference between the uplink and downlink propagation delays for the S-cell: Δ _SCell-PCell PD _UL = Δ _SCell-PCell PD _DL + Δ _SCell PD _UL-DL (Equation 8)
Is the formula TA _SCell = TA _PCell + 2 · Δ _SCell-PCell PD _DL −Δ _SCell PD _UL-DL (Formula 11)
Bring.

Δ _SCell-PCell Rx _DL is the difference in downlink reception time between P cell and S cell, ie, reception at UE3 of downlink transmission from eNodeB on P cell and down from eNodeB on S cell The difference in time between the transmission of the link in UE3 and the _{ΔSCell-PCell} Tx _DL is the difference in the downlink transmission time between the P cell and the S cell, i.e. down to UE3 on the P cell. Substitution _{ΔSCell−PCell} PD _DL = _{ΔSCell−PCell} Rx _DL − which is the time difference between the transmission in the link eNodeB and the transmission in the downlink eNodeB to the UE 3 on the S cell _{ΔSCell-PCell} Tx _DL (Formula 12)
Is a formula TA _SCell = TA _PCell + 2 · (Δ _SCell-PCell Rx _DL −Δ _SCell-PCell Tx _DL ) −Δ _SCell PD _UL-DL (Formula 13)
= TA _PCell + 2 · _{ΔSCell-PCell} Rx _DL -2 · _{ΔSCell-PCell} Tx _{DL -ΔSCell} PD _UL-DL (Formula 14)
Bring.
In other words, the S cell timing advance can be calculated based on:
● P cell timing advance ● Difference in downlink reception time between P cell and S cell ● Difference in downlink transmission time between P cell and S cell ● Uplink and downlink on S cell Difference in propagation delay between

  Basically, the P cell timing advance is known to both eNodeB and UE3.

The downlink reception time difference between the P cell and the S cell (Δ _SCell-PCell Rx _DL ) is not known at the eNodeB, but can be measured at the UE side.

As will become clearer in connection with FIG. 27, the difference _{ΔSCell-PCell} Tx _DL in the downlink transmission time between the P cell and the S cell is known only by the eNodeB and not known to the UE3. In the particular embodiment of FIG. 26, the downlink transmission time difference ( _{ΔSCell−PCell} Tx _DL ) between the P cell and the S cell is 0, with respect to the embodiment of FIG. 27 described later. The difference in downlink transmission time between the P cell and the S cell (Δ _{SCell−PCell} Tx _DL ) is not zero.

With reference to the examples of FIGS. 15, 16, and 17, the definition of the timing advance TA _SCell of Equation 13 and Equation 14 is the difference in downlink transmission time between P and S cells (Δ _{SCell−PCell} Tx _DL ) and the propagation delay difference between the uplink and downlink on the S cell ( _ΔSCell PD _UL-DL ) is further considered and is therefore more accurate. In other words, as considered in connection with FIG. 26, there is no transmission time difference between the P cell and the S cell (Δ _SCell-PCell Tx _DL = 0), and the uplink and downlink on the S cell. In a mobile communication system configured to operate with no difference in propagation delay between (Δ _SCell PD _UL-DL = 0), Equation 14 corresponds to the example equations of FIGS. .

  The difference in propagation delay between the uplink and downlink of the serving cell S cell is assumed to be negligible for the purposes of the present invention. More specifically, the propagation delay in the uplink and downlink directions is assumed to be the same for each carrier. Simulations performed by 3GPP WG RAN4 show that for the same receiving node (ie, eNodeB), the difference in propagation timing is less than 1 TA step (approximately 0.5 μs) in the 97-98% case, and in the 100% case This resulted in a simulated propagation delay difference for in-band carrier aggregation indicating less than 5 TA steps. Accordingly, for DL and UL carrier pairs linked with SIB-2, the frequency gap between uplink and downlink is much smaller than between different frequency bands, resulting in a given The difference in propagation timing between the UL and DL directions for a given cell is much smaller and is therefore negligible for the present invention.

Assuming the above contents and considering that the mobile terminal UE calculates the S cell timing advance, the mobile terminal UE is defined by the following Equation 15, that is, the P cell timing advance ( TA _PCell ) and the timing advance for uplink transmission on the S cell may be approximated based on the difference in downlink reception time between the P cell and the S cell (Δ _{SCell−PCell} Rx _DL ). it can. For the mobile communication system illustrated in FIG. 27 with different uplink timing advance for P cell and S cell 1 / S cell 2, the timing advance determined by the mobile terminal is S cell 1 / S cell 2 Note that it only approximates the exact timing advance for.

In a future release, there is a possibility that the mobile terminal UE performs uplink transmissions to different eNodeBs simultaneously, i.e. cooperative multi-point (COMP) transmission in the uplink. is there. Since two different eNodeBs are not required to use the same downlink timing, the difference in transmission time between the first _eNodeB1 that provides the P cell and the eNodeB2 that provides the S cell (Δ _SCell-PCell Tx _DL ) Need to be considered when aligning the time of uplink transmission on the S cell. Without this value, the mobile terminal can still only approximate the timing advance for uplink transmission on the S cell.

  Thus, based on the measurements performed by the mobile terminal and / or the uplink time alignment information for the S cell determined by the mobile terminal, only the eNodeB is able to perform the uplink operation performed by the mobile terminal on the S cell. An accurate time alignment of the transmission can be guaranteed. In other words, if the transmission of this timing information by the mobile terminal to the eNodeB is, for example, coordinated multipoint (COMP) transmission, the eNodeB accurately controls the time alignment process for the S cell at the mobile terminal. to enable.

  As a result of the above considerations, a more detailed embodiment of the present invention for S-cell uplink time alignment for UE3 is shown below with reference to FIG.

In Step 1 of FIG. 25, UE3 receives the difference in downlink reception time Δ _SCell-PCell Rx _DL , in particular, the time when UE3 receives the start of one subframe from the P cell, and UE3 receives from the P cell. Measure the time difference between the received time of the corresponding start of one subframe from the S cell that is temporally closest to that subframe. Correspondingly, UE3 performs measurements on each of the two S cells resulting in _{ΔSCell1-PCell} Rx _DL and _{ΔSCell2-PCell} Rx _DL . In this scenario, the difference in downlink reception time is substantially the same for S cell 1 and S cell 2. The difference in downlink reception time for one S cell can be seen in FIG.

In step 2, UE3 calculates the timing advance regarding the S cell using the measurement result. Since the difference in downlink reception time is the same for both S cells, UE3 calculates only one timing advance that can be used by UE3 to align the uplink times of both S cells. Considering the assumption of this embodiment, since _{ΔSCell-PCell} Tx _DL and _ΔSCell PD _UL-DL can both be considered to be 0, Equation 14 discussed above is
TA _SCell = TA _PCell + 2 · Δ _SCell-PCell Rx _DL (Formula 15)
Can be written concisely as

Thus, the mobile terminal uses the received downlink reception time difference (s) _{ΔSCell1-PCell} Rx _DL / _{ΔSCell2-PCell} Rx _DL and a known time advance for the P-cell. Then, time advance TA _{SCell1 / SCell2} for S cell 1 and S cell 2 is calculated according to Equation 15.

In step 4b in FIG. 25, UE3 as a result of the measurement, namely, the timing which is calculated regarding the difference in the reception time of the downlink Δ _{SCell1-PCell Rx DL} and / or Δ _{SCell2-PCell Rx DL,} and / or S cells Advance TA _{SCell1 / SCell2} is transmitted to the eNodeB, preferably using the PUSCH of the P cell. Alternatively, since the difference in reception time of both downlinks is the same, UE3 may only send one of the two measurements and / or one of the calculated timing advance. is there.

In step 3, UE3 is calculated relative to the start of the downlink radio frame of S cell 1 and S cell 2 in the same way that standard initial timing advance is applied by the UE. Timing Advance TA _{SCell1 / SCell2} is applied.

  In this way, UE 3 can align the uplink times of S-cell 1 and S-cell 2 and can start uplink transmission on those S-cells according to the received uplink scheduling grant. . The initial uplink grant is usually part of the RAR message within the standard RACH procedure. In the present invention, since the RACH procedure is not performed on the S cell, the initial uplink grant for the S cell can be sent to the UE 3 in any manner at any time via the PDCCH.

UE 3 sends uplink transmissions to the eNodeB using the uplink grants for S cell 1 and S cell 2. This is illustrated in FIG. 25 for one S cell. UE3 “shifts” by the timing advance value T _{SCell1 / SCell2} so that the uplink radio frame for the S cell is relative to the reception time T _{DL_RX_SCell} for the downlink radio frame for the S cell. A transmission time T _{UL_TX_SCell} is set.

Such timed uplink transmissions on the S cell are received at the eNodeB at T _{UL_RX_SCell} after the propagation delay PD _{UL_SCell} .

Downlink reception time difference Δ _SCell1-PCell Rx _DL and / or Δ _SCell2-PCell Rx _DL and / or information on calculated timing advance TA _{SCell1 / SCell2} for S cell from UE3 in step 4b , ENodeB is enabled to control time alignment of uplink transmissions on the S cell (step 7).

In particular, as described above, the UE 3 sends the downlink reception time difference and / or the calculated timing advance to the eNodeB, providing the eNodeB with information that the eNodeB cannot measure or derive by itself. Based on the downlink reception time difference _{ΔSCell1-PCell} Rx _DL and / or _{ΔSCell2-PCell} Rx _DL and / or the calculated timing advance TA _{SCell1 / SCell2} for the S cell, the eNodeB is used in the S cell It can be determined whether the time advance to be made allows transmission of the precisely timed uplink by UE3 on the S cell.

Illustratively, determining whether the timing advance TA _{SCell1 / SCell2 for the} received S cell (calculated by UE3 in step 2) allows sufficient time alignment of uplink transmissions on the S cell. To do. To that end, the eNodeB determines the received value from three values according to Equation 14, eNodeB: P cell timing advance, downlink reception time difference between P and S cells, and P cell And the timing advance value for the S cell determined based on the difference in downlink transmission time between the S cell and the S cell. If the difference between the received timing advance for the S cell and the determined timing advance is greater than the threshold, the eNodeB determines that the timing advance to be used in the S cell is accurate by UE3 on the S cell. It is determined that the uplink transmission at the same time is not allowed.

  This exemplary determination of whether the timing advance calculated by UE3 is sufficient to time the uplink transmission on the S cell is performed by UE3 on the S cell when the actual uplink transmission is performed Can be done before being done.

Alternatively, determine whether the timing advance TA _{SCell1 / SCell2 for the} received S cell (calculated by UE3 in step 2) allows accurate time alignment of uplink transmissions on the S cell To do. Therefore, the eNodeB ensures that the downlink reception time difference measured by the UE3 between the P cell and the S cell is accurate based on its eNodeB knowledge of the radio cell arrangement of the mobile communication system. It can be determined whether or not it is visible. Alternatively, the eNodeB can distinguish based on the threshold whether the received timing advance is sufficient to align the time of uplink transmission by UE3 on the S cell. The determination whether the timing advance calculated by UE3 is sufficient to align the time of uplink transmission on the S cell is again performed by UE3 on the S cell. Can be done before being done.

Furthermore, other exemplary implementations for the eNodeB to determine whether the timing advance calculated by UE3 is sufficient to align the time of uplink transmission on the S cell are as follows: 2) Calculated timing advance for S cell _Relies on performing the actual uplink transmission on the S cell applying TA _{SCell1 / SCell2} . For uplink transmissions of mobile terminals on the S cell, the eNodeB determines the reception time for uplink transmissions on the S cell uplink, a predefined criterion for uplink transmissions on the S cell uplink. There is a possibility to compare with time. Or, the eNodeB may compare the reception time of the uplink transmission on the uplink of the S cell with the transmission time of the downlink transmission on the corresponding downlink of the S cell.

If the eNodeB determines in step 7 that the calculated timing advance TA _{SCell1 / SCell2} for the S cell does not allow UE3 to transmit the timed uplink accurately, the eNodeB calculates in step 8 And the transmitted timing advance TA _{SCell1 / SCell2} cannot be used by UE3 to align the time of uplink transmission on the S cell, ie the calculated and transmitted timing advance TA _{SCell1 / SCell2} is S Transmit information informing UE3 that it is not possible to transmit uplinks on the cell that are precisely timed.

  According to an example, this information may include a RACH command that triggers the mobile terminal to perform a random access procedure in at least one of the S cells when a RACH command message is received (step 9). As part of the random access procedure, UE3 receives the exact timing advance for the S cell (s) and uplink targets based on the timing advance received within the random access procedure. Align the time of the S cell (s) by adjusting the timing for uplink transmissions on the cell.

  According to another example, this information may be obtained by adjusting the uplink (1) by adjusting the timing for uplink transmission on the uplink target cell based on the timing advance received when the timing advance is received. It may include a timing advance command with timing advance for use in the S cell that triggers the mobile terminal to align the time of the S cell (s) (step 9).

  According to a further example, this information may be transmitted for uplink transmission on the uplink of the target timing advance update value (s) and S cell (s) included when the timing advance update command is received. Determine a timing advance for use in the uplink of the S cell (s) based on the timing advance used and on the uplink target cell based on the determined timing advance A timing advance update command may be included to trigger the mobile terminal to align the time of the S cell (s) by adjusting timing for uplink transmission (step 9).

FIG. 27 shows a timing diagram according to another embodiment of the present invention. Compared to the timing diagram of FIG. 26, the difference is that the P cell and S cell perform downlink transmissions at different times, ie the timing of the downlink subframe is synchronized between the P cell and S cell. It is not. Further, it is assumed that S cell 1 and S cell 2 have the same downlink transmission timing. In other words, there is a downlink transmission time difference Δ _SCell-PCell Tx _DL between P cell and S cell that is not 0 but the same for S cell 1 and S cell 2.

  The uplink time alignment procedure already described in connection with FIG. 25 can be similarly applied to the scenario illustrated in FIG. 27, taking into account the following procedure changes.

UE3 can _measure the difference _{ΔSCell1-PCell} Rx _DL and / or _{ΔSCell2-PCell} Rx _DL of the downlink reception time that is the same for S cell 1 and S cell 2 (step 1 in FIG. 25). The difference in downlink reception time is not only the difference in propagation delay between the P cell and S cell (as in FIG. 26), but in this case the difference in downlink transmission time Δ _SCell-PCell Tx _DL Note that also consider.

In this particular embodiment of the invention, the measured downlink reception time difference _{ΔSCell-PCell} Rx _DL is longer than the difference in propagation delay between the P cell and the S cell, ie, between the P cell and The difference in downlink transmission time between S cells is longer by Δ _SCell-PCell Tx _DL .

However, since the downlink transmission time difference Δ _SCell-PCell Tx _DL between the P cell and the S cell is unknown to UE3, that is, is transparent, UE3 is up on the S cell based on Equation 15. Timing advance for link transmission is calculated (step 2 in FIG. 25). In particular, the UE 3 may determine the timing advance based on the P cell timing advance (TA _PCell ) and the difference in downlink reception time between the P cell and the S cell (Δ _SCell-PCell Rx _DL ). Assume that

Illustratively, then, UE 3 may use the result of the measurement, ie the difference in downlink reception time Δ _SCell-PCell Rx _DL and / or the calculated timing advance TA _SCell for the S cell, preferably for the P cell. It transmits to eNodeB by using PUSCH (step 4a of FIG. 25).

When this value is received, the eNodeB determines that the eNodeB has three values: the P cell timing advance, the downlink reception time difference between the P cell and the S cell, and the P cell and S The timing advance value for the S cell determined based on the difference in downlink transmission time between the cells can be compared by subtraction. Since the value received from UE3 does not take into account the difference in downlink transmission time between the P and S cells (Δ _SCell-PCell Tx _DL ), this difference is greater than the threshold.

Thus, the eNodeB can determine that the timing advance calculated by the UE 3 for use in the S cell does not allow transmission of the precisely timed uplink on the S cell (step of FIG. 25). 7) Then use the following Equation 16 for alignment of uplink transmission by UE3 on S cell: That is, only _ΔSCell PD _UL-DL is set to 0 for the reason already described.
TA _SCell = TA _PCell + 2 · Δ _SCell-PCell Rx _DL -2 · Δ _SCell-PCell Tx _DL (Formula 16)

Illustratively, the eNodeB transmits the determined timing advance TA _SCell to the UE 3 according to step 8 shown in FIG. In response, UE 3 sends the received timing advance value TA _SCell to the uplink on S cell 1 and S cell 2 relative to the beginning of the downlink radio frame on each S cell 1 and S cell 2. Are used to align the transmission times of the messages (step 9 in FIG. 25). Alternatively, the eNodeB sends a RACH command or a timing advance update command as already described.

  Even if the eNodeB knows the timing advance used by the UE for uplink transmission on the P-cell, the UE's autonomous change of uplink timing according to TS 36.133 section 7.1.2 Note that it causes some derivation from the timing advance value of the P cell signaled from the eNodeB to the UE, except just after the transmission of the PRACH. Thus, according to another alternative embodiment, the UE may transmit the DL radio frame received on the P cell and the UL transmitted on the P cell in addition to the measurement of the difference in downlink reception time. The used difference between the radio frames is also reported to the eNodeB.

  FIG. 28 discloses a flowchart diagram illustrating the various steps performed by the mobile terminal UE to enable transmission of timed uplinks according to a time alignment procedure according to an exemplary embodiment of the present invention. .

  In the time alignment procedure according to this exemplary embodiment of the invention, the eNodeB or aggregation access point is a node that controls the timing of the uplink used by the mobile terminal for transmission on the uplink of the cell. is there. Even though the mobile terminal can autonomously calculate the timing advance for the target cell (eg, S cell or group of S cells), the aggregation access point can always use this self-calculated timing advance. Overriding and instructing the mobile terminal to use another timing advance determined and signaled by the aggregation access point. In this case, the mobile terminal uses the timing advance signaled from the aggregation access point. In other words, the timing advance signaled by the aggregation access point takes precedence over the timing advance calculated autonomously by the mobile terminal.

  In the following, modifications and additional steps of the above-described embodiment will be shown with reference to FIG.

Trigger report step by UE In the above embodiment, it is touched when the UE starts a measurement (step 1a) and a report of the measurement result and / or the calculated timing advance (step 1c). There wasn't. The measurement can be performed periodically, for example.

  Reporting / signaling can be performed either periodically or in an event triggered manner.

  For example, in step 1) of FIG. 28, the periodic triggering of the report may be similar to the mobility or power headroom or buffer status report. The advantage of periodic reporting is that the eNodeB gets up-to-date information on measurement results and / or calculated timing advance at a specific period. Thus, the eNodeB is enabled at periodic intervals to determine whether the timing advance calculated by the UE is sufficient for time alignment of uplink transmissions on the S cell, thereby The timing advance of the UE can be continuously controlled when necessary.

  However, event-triggered reports are equally useful in step 1) of FIG. 28, for example to allow eNodeB to react quickly to prevent interference due to incorrect uplink time alignment. May be necessary. Several events are described below.

  The configuration of the S cell may be used as a trigger for the UE to initiate a measurement result and / or calculated timing advance report (step 1c) to the eNodeB (step 1b is optional). Measurements and reports are made according to one exemplary embodiment for the S cell (s) being configured and deactivated. Providing the eNodeB with measurement results and / or calculated timing advance each time a new S-cell is configured has a further advantage (step 1c).

  More specifically, the eNodeB is given the opportunity to see if a different timing advance (multi-TA) is needed for the newly configured S-cell. Further, accordingly, the eNodeB can optionally compute the exact timing advance for the UE to be used in the S cell, and optionally signal that timing advance to the UE. (Step 4 in FIG. 28). In other words, even if the S cell is deactivated (ie not used for transmission), the UE already knows which timing advance to use for this S cell.

  Thus, when the S cell is activated, the UE can immediately apply the previously received timing advance for the S cell and transmit already with the correct uplink time alignment (step 4a). Thus, for example, S cell activation is faster when compared to an approach where RACH needs to be performed on the newly activated S cell to achieve uplink synchronization. Basically, the activation delay for the S cell is the same as Rel-10, where the S cell has the same timing advance as the P cell when using the present invention.

  Alternatively, S cell activation can be used by the UE as a trigger to initiate a measurement (step 1a) and a report of the measurement results and / or the calculated timing advance (step 1c) (step 1b is optional). An advantage of using activation as a trigger is that when an eNodeB activates an S cell, the eNodeB also intends to schedule transmissions on the S cell. It may be beneficial to provide the eNodeB with the latest measurement results and / or calculated timing advance to determine the correct timing advance used for uplink transmission on the activated S-cell. is there.

  Another option to be used as a trigger is that the mobile terminal receives a specific request from the eNodeB to report measurement results and / or calculated timing advance to the eNodeB. This allows the eNodeB to determine for each case whether a report of measurement results and / or calculated timing advance is required.

  There are several possibilities how to send this request from the eNodeB to the mobile terminal. For example, an RRC message constituting an S cell, for example, a flag in an RRC connection reconfiguration message may explicitly request a report of measurement results.

  Alternatively, the activate / deactivate command (MAC CE) shown in FIG. 29 may include a flag that explicitly indicates the need for timing information reporting, i.e., eNodeB has been measured and / or calculated Explicitly request the mobile terminal to report timing advance.

  The flag may be signaled by using an empty “reserved bit” in the activation / deactivation MAC control element. The activation / deactivation MAC control element actually activates or deactivates any of the S cells since activation of already activated S cells is supported (also called reactivation). Can be sent by the eNodeB at any time to request a report of the measurement results.

  Another possibility is to reuse the so-called “RACH command” message corresponding to the message 801 in FIG. 8, which is physical layer signaling (PDCCH using DCI format 1A). Several predefined codepoints or combinations of field codepoints in the RACH order for the S cell may be used as a report request. For example, a RACH command for an S cell with ra-PreambleIndex set to “000000” (ie, usually indicating that the UE should perform contention based RACH) is re-requested to request a report. Can be defined. Alternatively, a predefined carrier indicator (CI) code point for the case of cross-scheduling can be used as a request. The advantage is that the uplink resource allocation that the mobile terminal will send the measurement results and / or the calculated timing advance can be sent together with the request for measurement and / or report, and thus the report delay Is to reduce.

  Another trigger event for reporting (step 1c) the measurement result and / or the calculated timing advance (optional step 1b) is performed in connection with the uplink time alignment of the S cell. Measurement results may exceed certain preconfigured thresholds.

  Such a report by the UE is particularly beneficial if the eNodeB does not know the need to use a timing advance for the S cell that is different from the P cell timing advance. The eNodeB does not always have sufficient knowledge from, for example, OAM (operation / management / maintenance that normally provides cell placement information such as the presence of repeaters or RRHs).

  Also, the need for multi-timing advance depends on the location of the UE (see FIG. 26 and corresponding description). Thus, for example, a frequency selective repeater may be transparent to the eNodeB and is made visible to the eNodeB only by the UE reporting on large downlink reception time differences. Alternatively, even if the eNodeB is aware of the FSR, the eNodeB does not know exactly when the UE will no longer receive S-cells via the FSR rather than from the eNodeB.

Trigger of time alignment step by UE Similar to the above-described embodiment, the mobile terminal UE shown in FIG. 28 measures the difference Δ _SCell-PCell Rx _DL in the downlink reception time between the S cell and the P cell. (Step 2a), the difference in reception time between the S cell and the P cell Δ _SCell-PCell Rx _DL and on the S cell based on the timing advance used for uplink transmission on the P cell Timing advance TA _SCell for uplink transmission is calculated (step 2b). Next, the mobile terminal UE aligns uplink transmission times on the S cell based on the calculated timing advance for the uplink S cell (step 2c).

  However, in the above-described embodiment, it is much touched when the UE aligns the time of uplink transmission on the S cell and how the timing alignment is updated with respect to the S cell over time. There wasn't.

  Time alignment for S cells can be performed either periodically or in an event triggered manner. In particular, an event-triggered time alignment procedure is advantageous with respect to the initial time alignment of the S cell uplink transmission. Periodically triggered time alignment ensures that uplink transmissions performed by the mobile terminal UE remain in time even when the S cell timing advance is not controlled by the eNodeB.

  With respect to event-triggered timing alignment of uplink transmissions on the S-cell, the same triggering mechanism as described in connection with event-triggered reports may be used. In particular, the UE may be configured to use the S cell configuration as a trigger to initiate the S cell timing alignment procedure. Alternatively, S cell activation may be used by the UE as a trigger to initiate the S cell timing alignment procedure. Another alternative event for triggering the S cell timing alignment procedure is when the mobile terminal UE receives a specific message from the eNodeB requesting the start of the S cell time alignment procedure.

  Similarity between measurement for report (step 1a) and measurement for time alignment (step 2a), and calculation of timing advance for report (step 1b) and timing for time alignment -Due to the similarity between the advance calculation (step 2b), the mobile terminal, according to another exemplary implementation, for the measurement result and / or the calculated timing advance report on the S-cell Step (step 1c) as well as the step for time alignment of uplink transmissions on the S cell (step 2c) can be performed at the same time, thus requiring only one event trigger.

  A time alignment procedure performed periodically is illustrated in FIG.

  In FIG. 28, the mobile terminal UE uses a timer to ensure that uplink transmissions remain in time. A separate timer may be held by the mobile terminal for each timing advance value (each associated with either an individual uplink cell or a group of uplink cells).

  The mobile terminal either (i) applies the calculated timing advance (step 2d) or (ii) executes the RACH procedure (step 3c) or (iii) has a timer Each time the received timing advance value for uplink transmission on each P-cell or S-cell is applied, the timer is reset and started. In this regard, as long as the timer is running, the mobile terminal UE considers the mobile terminal UE itself to be in uplink synchronization.

  Whenever the timer expires (step 2), i.e., timing alignment is considered lost, the mobile terminal uses the mechanism described herein to re-time alignment for uplink transmission on the S cell. Establish.

  For example, the mobile terminal can align the time of the uplink transmission timing of the S cell using the newly determined timing advance for the S cell (step 2c).

  When re-establishing the timing alignment for the S cell, the mobile terminal UE considers the mobile terminal UE itself to be uplink-synchronized and resets and starts the timer (step 2d).

Determining Timing Advance for S Cell As described with reference to FIGS. 26 and 27, the mobile terminal determines the difference between the measured downlink reception time Δ _SCell-PCell Rx _DL and the uplink on the P cell. Time alignment on the S cell can be (re-) established by calculating a timing advance value based on the timing advance used for transmission.

Alternatively or additionally, the mobile terminal, the difference delta _SCell-PCell reception transmission time between the P cells and S cells Rx DL _{-Tx UL} measured, the difference between the received transmission time Δ _{SCell-PCell Rx DL} Timing advance calculated based on Tx _UL and / or its received transmission time difference Δ _SCell-PCell Rx _{DL -} Timing advance used for transmission of uplink on Px _UL and P-cell Can be reported.

26 or 27 also shows as follows.
_{ΔSCell-PCell} Rx _DL -Tx _UL = T _{DL_RX_SCell} -T _{UL_TX_PCell}

  In other words, the difference in reception and transmission time between the P cell and the S cell is that the time when the mobile terminal transmits an uplink radio frame on the P cell and the time that the mobile terminal transmits a downlink radio frame on the S cell It is the time difference from the time to receive. Uplink radio frames and downlink radio frames refer to the same radio frame number.

As can be seen from either FIG. 26 or FIG. 27, the difference in downlink reception time _{ΔSCell−PCell} Rx _DL is _{equal to} the difference in reception transmission time _{ΔSCell−PCell} Rx _DL −Tx _UL and the timing of the P cell. Based on the advance TA _PCell , specifically, _{ΔSCell−PCell} Rx _DL = _{ΔSCell−PCell} Rx _DL −Tx _UL −TA _PCell (Formula 17)
Where TA _PCell can also be replaced by the measured time between _{TUL_TX_PCell} and _{TDL_RX_PCell} . The measured time between _{TUL_TX_PCell} and _{TDL_RX_PCell} may also be reported to the eNodeB along with the difference in received transmission time.

  Measuring and reporting the difference in received transmission time instead of, or in addition to, the difference in downlink reception time may be useful for future applications such as uplink coordinated multipoint (COMP) transmission. In terms of technology, the difference in received transmission time is beneficial because it can be used to control uplink transmission timing. Furthermore, it may be more preferable from an implementation perspective to measure and report the difference in received transmission time instead of or in addition to the difference in downlink reception time.

And the difference in received transmission time Δ _SCell-PCell Rx _DL -Tx _UL is used by the mobile terminal UE to calculate the timing advance for the S-cell and / or reported to the eNodeB, where eNodeB is also The difference _{ΔSCell−PCell} Rx _DL of the downlink reception time is calculated using Equation 17. Based on the calculated downlink reception time difference, the mobile terminal and / or eNodeB can calculate the timing advance for the S-cell as previously described and described in more detail later.

  Note that the mobile terminal can count the number of samples, for example, as a method of determining the time difference. For example, to determine the difference in downlink reception time, the mobile terminal counts the number of samples between the reception time of the downlink subframe in the P cell and the reception time of the downlink subframe in the S cell. . For example, a downlink subframe may refer to a common reference signal (CRS).

Report of measurement result After performing the measurement (step 1a), the mobile terminal transmits the result to the eNodeB. As already explained, the measured values are the difference in downlink reception time Δ _SCell-PCell Rx _DL and / or the difference in reception transmission time between P and S cells Δ _SCell-PCell Rx _DL -Tx _UL . (Step 1c).

  The report itself can in principle be implemented in several layers, for example the RRC layer or the MAC layer. Other measurements such as mobility or location measurements are also signaled at the RRC layer. Since the timing advance command is generated by the MAC layer, it may be beneficial from an implementation point of view to implement the measurement result report in the MAC layer.

  FIGS. 29 and 30 show the format of a MAC control element that can be used to transmit measurement results from the mobile terminal to the eNodeB. As is apparent, the structure of this MAC CE is similar to the extended power headroom MAC CE. The size depends on the number of S cells configured or configured and activated, i.e. the number of S cells on which measurements and reports are to be performed.

  More particularly, FIG. 29 shows a MAC control element for transmitting the downlink reception time difference between the P cell and all available S cells 1-n.

On the other hand, FIG. 30 shows a MAC control element for transmitting the difference in reception transmission time between the P cell and all available S cells 1 to n. In an alternative embodiment, this information should not be reported to the eNodeB, since the time between T _{UL_TX_PCell} and T _{DL_RX_PCell} corresponds to the TA _PCell and therefore should actually be known by the eNodeB.

  Instead of reporting downlink reception time differences and / or reception transmission time differences for all S-cells, the mobile terminal may report them only for specific S-cells to be timed.

  Furthermore, instead of reporting the downlink reception time difference and / or reception transmission time difference for all S cells, the mobile terminal aligns the time based on the calculated timing advance value as described above. There is a possibility to report the calculated timing advance for the S cell to be done.

  In addition, the time difference may be encoded and indicated by the number of samples, i.e. the mobile reports a specific number of samples, and then the eNodeB uses the number of samples and the time of the samples to calculate the actual time difference. There is a possibility of deriving.

  As already mentioned before, the measurement results are preferably transmitted on the P-cell physical uplink shared channel, PUSCH.

Determining Timing Advance for S-Cell In the above-described embodiment of the present invention, the mobile terminal and / or eNodeB can determine the timing advance value known from the standard RACH procedure, ie as illustrated in FIGS. It was assumed to calculate the timing advance (see arrow TA _SCell ) applied by the mobile terminal relative to the start of the downlink radio frame received via the downlink S cell.

  This is because the timing advance value is the same type as the timing advance defined by the standard and is defined relative to the downlink reception of the radio frame of the S cell, not to the P cell. So it may be called an absolute value.

  But there are other alternatives. The timing advance calculated by the mobile terminal and / or eNodeB and applied by the mobile terminal UE need not be relative to the start of the downlink radio frame received via the downlink S cell. Other criteria may be selected.

For example, the calculated and applied timing advance is relative to the beginning T _{DL_RX_PCell} of the downlink radio frame received via the P cell, or the uplink transmitted via the P cell. _{May be} relative to the start of _{TUL_TX_PCell} .

If the timing advance is calculated relative to the beginning of the uplink radio frame transmitted over the P cell, basically the timing advance is the timing advance between the P cell and the S cell. Advance difference _{ΔTA PCell-SCell} .

Considering Equation 14,
_{ΔTA PCell-SCell} = + 2 · Δ _SCell-PCell Rx _DL -2 · Δ _SCell-PCell Tx _DL -Δ _SCell PD _UL-DL
It is.

Therefore, the timing advance determined by the mobile terminal UE and / or eNodeB is _{ΔTA PCell-SCell} .

As described with reference to FIGS. 26 and 27, the mobile terminal transmits the downlink transmission time difference between the P cell and the S cell (Δ _{SCell−PCell} Tx _DL ) and the uplink and downlink on the S cell. I do not know about the difference in propagation delay between links ( _ΔSCell PD _UL-DL ). Accordingly, the timing advance _{ΔTA PCell-SCell} is determined on the assumption that both the values _{ΔSCell-PCell} Tx _DL and _ΔSCell PD _UL-DL are 0.

In contrast, the eNodeB may use a timing advance _{ΔTA PCell-SCell} , for example, to see if measurements performed by the mobile terminal UE allow sufficient time alignment of uplink transmissions on the S cell. When determining, the eNodeB determines the difference in downlink transmission time between the P and S cells (Δ _{SCell−PCell} Tx _DL ) and the difference in propagation delay between the uplink and downlink on the S cell (Δ _SCell PD _UL-DL ) can determine the timing advance _{ΔTA PCell-SCell} based on further knowledge of that eNodeB.

And this time, the mobile terminal applies this value relative to the start of the uplink radio frame received via the P cell, and the uplink for uplink transmission performed on the S cell. Determine the timing. This is illustrated in FIG. 31, where the timing advance is indicated by the number of samples N _TA and the actual to be applied for the uplink transmission in the S cell compared to the uplink transmission in the P cell. Multiply by the sample time T _S to obtain the time difference.

If the timing advance is calculated relative to the start of the downlink radio frame received via the downlink P-cell, the timing advance value can be inferred from FIGS. And TA _SCell + Δ _SCell-PCell Rx _DL .

Therefore, the mobile terminal first derives the current timing advance value TA _SCell, and _{subtracts the} downlink reception time difference Δ _SCell-PCell Rx _DL from the timing advance value TA _SCell .

  To set the timing of uplink transmission on the S-cell based on the received timing advance relative to the beginning of the downlink radio frame received by the mobile terminal in the P-cell Used for.

This is illustrated in FIG. 32, where the timing advance is indicated by the number of samples N _TA and the time of the samples to obtain the actual time difference to apply for uplink transmission in the S cell. It is multiplied by the T _S.

Random access channel, RACH, command reception As described in connection with the above embodiments, the mobile terminal transmits timing information to the eNodeB, which is related to the uplink of an S cell or a group of S cells. Allows you to control the timed process.

  With reference to FIG. 25, the eNodeB may obtain measurement results and / or calculated timing advance from the mobile terminal (eg, if the downlink transmission time difference between the P and S cells is non-zero). It has been described that it is possible to determine whether the transmitted information allows for accurate time alignment of uplink transmissions on the S cell.

  Alternatively, if the eNodeB does not allow accurate time alignment of the uplink transmission on the S cell (ie regardless of the received timing information), the P cell time alignment used by the mobile terminal UE There is also a possibility of judging.

  For example, when the eNodeB detects that the uplink transmission time alignment by the mobile terminal on the P-cell is not accurate, the eNodeB, according to an example, sends a random access channel, RACH, command message to the mobile terminal UE. May send immediately. In other words, if the mobile terminal attempts to use a timing advance for an S cell based on, for example, a timing advance that does not meet the uplink criteria for the P cell, the eNodeB immediately sends a RACH command message to the mobile terminal. By transmitting, interference during uplink transmission on the S cell can be prevented. An error in the uplink transmission timing advance on the P cell (ie, the reference cell) will spill over to the calculated timing advance for the uplink transmission on the S cell to be timed.

  As another example, the configuration of the P cell and S cell may also trigger the eNodeB to immediately send a random access channel, RACH, command message to the mobile terminal UE. Based on the specific configuration of the P-cell and S-cell, the eNodeB may assume that the calculation of timing advance for the S-cell by the mobile terminal does not allow accurate time alignment of uplink transmissions on the S-cell There is sex. For example, if the P-cell and S-cell are configured in frequency bands that are far apart, the eNodeB may determine that the mobile terminal cannot calculate the exact timing advance for the S-cell.

  If the eNodeB determines that the mobile terminal UE is unable to calculate a timing advance that accurately aligns the time of uplink transmission on the S cell, in one example, the eNodeB has a random access channel, RACH, command There is a possibility to send a message to the mobile terminal immediately. In other words, using the RACH command message, the eNodeB ensures robust time alignment of uplink transmissions on the S cell and prevents uncontrollable uplink timing advance deviations.

  Preferably, the RACH command message corresponds to message 801 in FIG. 8, which is physical layer signaling (PDCCH using DCI format 1A).

  In step 3 of FIG. 28, when the mobile terminal receives the RACH command message, the mobile terminal performs a random access procedure as described with reference to FIG.

  As part of the random access procedure (ie, step 802), the mobile terminal receives an accurate timing advance for the S cell. The mobile terminal then aligns the time of the S cells by setting the time advance for uplink transmission on the uplink target cell based on the timing advance received within the random access procedure (FIG. 28 step 3b).

  Thereafter, the mobile terminal resets and restarts each timing advance timer for the S cell or group of S cells for which the random access procedure has been executed (step 3c in FIG. 28).

Receiving Timing Advance Command Another alternative way for the eNodeB to control the uplink of the timed process for the uplink of an S cell or group of S cells is the transmission of a timing advance command.

  As described in connection with the above-described embodiment, the mobile terminal UE transmits timing information to the eNodeB, and the eNodeB transmits a specific S cell or a group of S cells in the same manner as the timing advance calculation by the mobile terminal. Allows calculating timing advance for uplink transmission above.

  In some cases (eg, when the downlink transmission time difference between P and S cells is non-zero), as described above, only the eNodeB is up on a particular S cell or group of S cells. A timing advance can be calculated that allows accurate time alignment of the transmission of the link.

  In such a case, the calculated timing advance may be transmitted to the mobile terminal using, for example, the downlink shared channel of the S cell to which the timing advance is applied.

FIG. 33 illustrates the format of a timing advance command to be used to transmit a calculated timing advance from the eNodeB to the mobile terminal according to one particular embodiment of the invention. If the timing advance information calculated and sent to the mobile terminal is TA _SCell (and is not part of the relative values mentioned above in connection with FIGS. 31 and 32), the initial TA as known from the standard In order to achieve the required granularity (same as command), 11 bits are preferably used to transmit the timing advance for the S cell.

  On the other hand, if the timing advance is smaller, it is relative to another timing, so fewer bits are sufficient.

  One example is to use a new MAC control element to carry timing advance information, eg, 8 bits. Alternatively, a timing advance update command known from Release 8 of LTE having the format shown in FIG. 33 may be used. One of the free R bits can be used to distinguish between the actual timing advance update command known from the standard and the timing advance information according to one of the various embodiments of the present invention.

  Since some embodiments use relative timing advance (see description associated with FIGS. 31 and 32), the 6 bits provided by the timing advance update command may provide sufficient granularity. .

  Another alternative is for the eNodeB to send timing advance information for all configured, configured and activated S cells, not just for one S cell. If the UE reports timing information for all configured or configured and activated S-cells according to the above embodiment, it makes sense to report all calculated TAs accordingly. there is a possibility.

  In Step 4 of FIG. 28, when the mobile terminal UE receives a timing advance command from the eNodeB using one downlink shared channel of the S cell or the group of S cells to which the timing advance is applied. The mobile terminal UE aligns uplink transmission times using the carried timing advance value for the S cell or group of S cells (step 4a in FIG. 28).

  Thereafter, the mobile terminal resets and restarts the timer of each timing advance related to the S cell or the group of S cells to which time advance is applied (step 4b in FIG. 28).

S-cell grouping In the scenario envisaged for FIGS. 24, 25 and 26, S-cell 1 and S-cell 2 have the same propagation delay for S-cell 1 and S-cell 2, so Has advance. In the case described above, S cell 1 and S cell 2 may be said to form a timing advance group.

  In addition to this scenario, several individually configured and activated S forming different timing advance groups depending on whether the S cells can be timed on the uplink with the same timing advance value. There can be cells. As already explained, there are several reasons that lead to the need for different timing advance between different S cells of the same mobile terminal. An example is one or more frequency selective repeaters that amplify only some of the signals in the S cell.

  In any case, when the mobile terminal stores the mapping of the S cell to the specific timing advance group, it is necessary to align the times of the S cells 1 belonging to the timing advance group having the S cell 2 having the same time. When there is a mobile terminal, the mobile terminal can immediately apply the timing advance previously used to the S cell 2 with the same time, and can also adjust the uplink transmission time of the S cell 1. Thus, it is not necessary to perform all the steps of the present invention.

  The mapping of S cells to timing advance groups can only be configured and updated by the eNodeB.

  A further aspect of the invention is to align uplink times when serving cell times are not aligned. However, the following specific scenarios should not be understood as limiting the present invention, but as an example to illustrate the principles of the present invention. It is assumed that the reference cell is a P cell and the target cell is an S cell. It is assumed that the aggregation access point is an eNodeB.

For this aspect of the invention, the following definitions are provided.
The term “reference cell” refers to a cell (P cell or one of S cells) that is already ready for uplink transmission. Since the P cell is the most accurately timed cell thanks to the RACH procedure performed on it (RACH allows for absolute measurements and is therefore in some embodiments of the present invention. Therefore, it is advantageous to make the P cell the reference cell, which is more accurate than the relative measurements made. Nevertheless, any activated S-timed S cell that was previously timed according to the present invention can be a reference cell.

The term “aggregation access point” refers to a location in an access network, ie a node (eg, eNode or base), where user equipment uplink transmissions on different uplink component carriers are aggregated. Station). Such aggregation is
-Joint physical layer processing (eg, joint demodulation (eg, including the use of one IFFT (Inverse Fast Fourier Transform) to process received subframes in an OFDM system) and / or coded transport For the purpose of joint decoding of blocks, etc., radio signals corresponding to different uplink component carriers from the user equipment, i.e. transmissions on the physical layer (e.g. respective subframes), Receiving simultaneously by points,
And / or-processing protocol data units received in transmissions (eg, respective subframes) on different uplink component carriers from the mobile terminal at the protocol entity of the aggregation access point. Point to.

  The joint processing of protocol data units received in transmissions on different uplink component carriers from the user equipment is in one exemplary implementation, for example, aggregation aggregation, for the purpose of PDU reordering. It can be a joint processing of PDUs acquired from transmissions on different uplink component carriers at the MAC or RLC layer of the access point.

  The term “target cell” refers to a cell for which uplink transmission time is not yet available and is therefore subject to the time-aligned procedure of the present invention. According to the definition of “reference cell” above, the “target cell” is one of the S cells that most often does not have or lost the uplink time alignment. In special cases, i.e., if a P cell (initially time aligned using the RACH procedure) loses time alignment, the P cell may also be the target cell. In this case, the time alignment of the P-cell using the current time alignment procedure can be performed, and therefore the execution of the RACH procedure can be avoided, but the RACH procedure is more preferred.

  In this document, “simultaneously” or “at the same time” means being at the time of adding / subtracting a small deviation at the same time, which deviation can be within a certain range. For example, not only the granularity of the timing advance value, but also the slight difference between the uplink and downlink propagation delays in a given radio cell can be considered as a complete uplink transmission on UL P cells or UL S cells. Implies that there is no time alignment. In either case, the simultaneous arrival of uplink transmissions is such that uplink transmissions by mobile terminals via different uplink cells (with different propagation delays) can be handled together by the receiving aggregation access point. Synchronization is guaranteed. For example, different transmissions of one given subframe on the uplink cell may be timed so that they are received so that the aggregation access point can process all transmissions of the subframe together. Is complete.

  Furthermore, it is also noted that uplink cell time alignment configured for a mobile terminal is of course applicable if the mobile terminal must time two or more uplink cells. I want to be. Basically, as long as there is one reference cell that is time aligned, the procedure described herein can align the time of any number of uplink cells.

  The term “shift” is used in reference to shifting the transmission of uplink subframes by a specific time value relative to the reference, which is, for example, a downlink subframe received via a downlink reference cell. Can be the beginning of “Shift” means that the mobile terminal sets the transmission time when aligning the uplink time, that is, transmits the uplink frame at a time different from the reference by a specific time value. .

  The explanation given in the background section above is intended to better understand most of the technical fields of 3GPP LTE (Release 8/9) and LTE-A (Release 10). They should not be construed as limiting the invention to the described specific implementations of processes and functions in a mobile communication network. Certain exemplary embodiments described below may be implemented in LTE Release 11, which has recently been deliberated.

  FIG. 34 is a signaling diagram illustrating various steps performed by a mobile terminal and an eNodeB and messages exchanged between them to enable a time alignment procedure according to one embodiment of the present invention. Disclosure. The mobile terminal configured a P cell that exchanges data with the eNodeB via it. The P cell of the mobile terminal is already timed in the uplink, i.e., uplink transmissions performed by the mobile terminal via the P cell are those received at the eNodeB by other mobile terminals via the P cell. Executed by the mobile terminal at a timing that is synchronized with the reception of the uplink transmission. P-cells are initially timed in the uplink by performing a RACH procedure, as described in the background section, and are connection-based or non-connection-based (see FIGS. 7 and 8). Wanna) Although not very advantageous, it is theoretically possible to first synchronize the P-cells using the principles of the present invention, assuming the reference is an uplink S-time aligned S-cell. . However, in the following description, it is assumed that the P cell is first synchronized on the uplink using the RACH procedure, because the P cell aggregates multiple serving cells by the UE. For example, if the PUCCH is transmitted on a P-cell, the uplink is always synchronized and has the “best” uplink time alignment (because the RACH procedure is more accurate). It is.

  The mobile terminal is now composed of a secondary cell and an S cell, but the S cell does not have the uplink time yet. For example, the S cell has just been configured, or the S cell has previously had uplink time but has lost uplink synchronization (eg, timing advance timer has expired) ). In any case, the mobile terminal must now achieve uplink time alignment so that uplink data can be transmitted to the eNodeB via the S cell. The following steps are performed as illustrated by FIG.

  1. The mobile terminal performs measurements to determine specific timing information for transmission / reception in the P cell and / or S cell. As described in more detail below, there are various timing information that can be determined at the mobile terminal. The timing information that the terminal measures, in particular the timing information that is subsequently transmitted to the eNodeB, is already in time, and thus serves as a reference for the time alignment of the S cells, the P cell uplink Is such that it allows the eNodeB to determine the timing advance for the S cell. The information of the measurement sent to the eNodeB is not yet known to the eNodeB, and thus the transmission and / or reception timing information of the signal exchange performed on the P cell and / or S cell between the mobile terminal and the eNodeB, etc. , Such as for timings unknown to the eNodeB.

  2. The result of the measurement is transmitted to the eNodeB by the mobile terminal.

  3. The eNodeB uses the information received from the mobile terminal to determine the timing advance for the S cell, and the determination is based on the received information and information indicating the time alignment of the P cell uplink. Yes. There are various possibilities for achieving this, which will be described in more detail in the following description.

  4). In any case, the eNodeB can determine the timing advance for the S cell and to allow the mobile terminal to adjust the timing of uplink transmission for the S cell. Prepare corresponding timing advance information for the terminal and its S cell.

  This timing advance information transmitted to the mobile terminal can be similar to an absolute value, ie, the initial timing advance value known from the standard, which is the S cell from the eNodeB by the mobile terminal. Applies to the arrival time of the above downlink transmission. Alternatively, the timing advance information transmitted to the mobile terminal can be relative to the timing advance used for the P-cell, so that the mobile terminal can set its value to the time It is possible to apply to the time of uplink transmission to the eNodeB by the mobile terminal on the aligned P cell or to the time of arrival of the downlink transmission from the eNodeB on the P cell.

  5. Using the timing advance information received from the eNodeB, the mobile terminal can align the timing of the uplink transmission timing of the S cell. As just described, how accurately the timing of uplink transmission is adjusted depends on the specific contents of the timing advance information. One option is that the timing advance information includes the timing advance applied as an absolute value, in which case the timing advance value for the S cell is transmitted by the eNodeB in the downlink of the S cell. Is calculated against In the above case, the mobile terminal shifts the timing of uplink transmission by the amount of time indicated by the timing advance information with respect to the start of the downlink subframe received via the S cell. Alternatively, if the timing advance information received at the mobile terminal is relative to the timing advance of the P cell, the mobile terminal has been transmitted over the P cell that has the correct time The timing of the uplink transmission is shifted by the amount of time indicated in the time advance information for the beginning of the uplink subframe or for the downlink transmission on the P cell.

  The mobile terminal can time the uplink of the S cell and then begin sending scheduled uplink transmissions based on the previously received uplink grant.

  As explained above, there are various advantages provided by the present invention. First, a procedure is performed to apply different timing advance to different component carriers, ie cells. Therefore, in a situation where the propagation of the S cell is different from that of the P cell, the uplink timing can be adjusted separately for each cell. Furthermore, application of random access procedures in the S cell is avoided. As explained at the end of the background section, the RACH procedure introduces several problems, such as increased mobile terminal complexity, or complex prioritization rules for power limiting, or power amplifier issues. Furthermore, the uplink synchronization process of the present invention is faster than the approach when the RACH procedure is performed. As will be shown in detail later, this is particularly important for the activation of S-cells that do not have uplink time.

  In the following, more specific embodiments of the present invention will be described with reference to FIGS.

  FIG. 24 shows a scenario in which the P cell, S cell 1, and S cell 2 are served to UE1, UE2, and UE3, which are different UEs depending on the eNodeB. In addition, a frequency selective repeater (FSR) configured for the frequencies used by S cell 1 and S cell 2 is provided, and the FSR is transmitted on secondary serving cells S cell 1 and S cell 2 / Amplifies received signals, but does not amplify signals transmitted / received on P cells. As shown by FIG. 24, P cell coverage is greater than S cell coverage.

In the lower part of FIG. 24, the difference in downlink reception time (Δ _Scell-PCell Rx _DL ) between the S cell 1 or S cell 2 and the P cell at the mobile terminal is compared with the position of the UE in the cell. Are plotted. The difference in downlink reception time is between when the UE receives the downlink subframe from the eNodeB via the S cell and when the UE receives the downlink subframe from the eNodeB via the P cell. It is a difference.

  In this particular scenario, the different uplink timing advance required for P-cell, S-cell 1 and S-cell 2 will vary depending on the location of the UE. More specifically, FIG. 24 shows three UEs, where UE1 is located in A within the coverage of P cell, S cell 1 and S cell 2, and UE2 is the S provided by the eNodeB. UE 3 is placed in area B where coverage of cell 1 / S cell 2 and coverage of S cell 1 / S cell 2 provided by FSR overlap, and UE 3 provides coverage of S cell 1 / S cell 2 provided by eNodeB Is located outside C but inside C cell 1 / S cell 2 coverage provided by the FSR.

  From location A to location B, P cell, S cell 1 and S cell 2 are provided to the UE by the same transmitting node, eg, eNodeB. Therefore, the propagation delays of the three cells should be substantially the same, so the difference in downlink reception time should be ignored. As a result, the same timing advance can be used for P cell, S cell 1 and S cell 2. On the other hand, at location B, the S cell 1 / S cell 2 signal from the FSR is stronger than the S cell 1 / S cell 2 signal from the eNodeB, correspondingly, the UE 2 at location B A signal is received via the cell, and a signal is received from the FSR via the S cell 1 / S cell 2. As a result, the propagation is different between the P cell signal and the S cell 1 / S cell 2 signal, which results in different downlink reception timings between the P cell and the S cell 1 / S cell 2. As can be seen from the lower part of FIG. 24, a plot of the downlink reception time difference between P-cell and S-cell 1 / S-cell 2 measured by UE2 shows that UE2 (from eNodeB) At the moment of switching from the receiving path to another receiving path (from the FSR), it suddenly jumps to a specific value.

  At location B, the downlink reception time difference is the largest because in this exemplary scenario, the path length difference between the P cell path and the S cell 1 / S cell 2 path is also the largest. Because there is. The difference in downlink reception time is mainly the time when the FSR receives, processes and transmits the amplified signal of S cell 1 / S cell 2, so the difference in downlink reception time is Decreases as you move further toward the FSR, just minimum at the FSR. When going away from the FSR again, the difference in downlink reception time also increases again.

  Therefore, UE2 and UE3 cannot use the same timing advance for S-cell 1 / S-cell 2 as they used for P-cells, and separate uplink timing Advanced must be configured. However, in the current scenario, the propagation delays of S cell 1 and S cell 2 are the same, so the same timing advance can be used for S cell 1 and S cell 2.

  FIG. 35 is a signaling diagram illustrating the steps performed in accordance with one embodiment of the present invention, assuming the scenario based on FIG. In particular, it is assumed that UE 3 of FIG. 24 needs to perform uplink synchronization for S cell 1 and S cell 2. UE3 receives the downlink signal from the FSR on S cell 1 and S cell 2, and further receives and transmits the signal via eNodeB and P cell.

  FIG. 26 shows reception and transmission timings of frames transmitted on the P cell and the S cell. For ease of explanation, FIG. 26 shows only one S cell instead of both S cell 1 and S cell 2. The following description relating to the S cell of FIG. 26 is equally applicable to both S cell 1 and S cell 2.

As is apparent from FIG. 26, in this particular embodiment of the invention, it is assumed that both the P cell and the S cell transmit frames to the UE 3 on the downlink at the same time T _{DL_TX_PCell} and T _{DL_TX_SCell} . As will be explained later, this is not always the case. The eNodeB is already transmitting data on the P cell to the UE 3, and the eNodeB transmits, for example, a common reference symbol on the downlink on the S cell, which is then received by the UE 3.

Downlink transmission is performed at the same time, but the P cell and S cell have different propagation delays ( _{PDDL_PCell} , _{PDDL_SCell} ), so the reception of the downlink transmission by the UE is not simultaneous ( _{TDL_RX_SCell} , _{TDL_RX_SCell} ) . In particular, the S cell path goes to the FSR first and then to UE3, but the P cell path is shorter because it reaches UE3 directly.

The uplink transmission of the P cell is already _timed and occurs in T _{UL_TX_PCell} , where T _{UL_TX_PCell} is a downlink radio received on the P cell using the timing advance TA _PCell = 2 × PD _{DL_PCell.} The time is determined relative to the start of the frame, i.e. _{TUL_TX_PCell} = _{TDL_RX_PCell-} TA _PCell . Uplink transmissions on P cells from UE3 _arrives at the eNodeB _{T UL_RX_PCell} corresponding to _{T UL_TX_PCell} + _{PD UL_PCell, PD UL_PCell} is to be equal to _{PD DL_PCell,} or the difference between these is assumed that at least negligible.

  As is clear from FIG. 26 or FIG. 24, the timing advance already used for the P cell is not used for uplink transmission on the S cell for UE3 due to different propagation delays. Can not. Therefore, according to one of the various embodiments of the present invention, the uplink of the S cell for UE3 needs to be synchronized separately.

One of the main ideas of the present invention is that the uplink timing of the P-cell with the uplink time aligned, and in particular the timing advance used by the UE 3 to synchronize uplink transmissions in the P-cell. Use to determine the timing advance for the S cell. The following timing relationship represents the relationship between the timing advance TA _SCell for the S cell, the timing advance TA _PCell for the P cell, and other parameters.
TA _PCell = PD _{UL_PCell} + PD _{DL_PCell} (Formula 18)
_{TA SCell = PD UL_SCell + PD DL_SCell} = PD UL_PCell + PD DL_PCell - (Δ SCell-PCell PD DL + Δ SCell-PCell PD UL)
_{= TA PCell - (Δ SCell-} PCell PD DL + Δ SCell-PCell PD UL)
Where Δ _SCell-PCell PD _DL is the difference between the P cell and S cell propagation delays in the _downlink , and Δ _SCell-PCell PD _UL is the P cell and S cell propagation delay in the uplink. Is the difference between

You can replace
_{ΔSCell-PCell} PD _UL = Δ _SCell-PCell PD _DL + Δ _SCell PD _UL-DL (Formula 19)
Here, _ΔSCell PD _UL-DL is the difference between the S cell uplink and downlink propagation delays, and the following equation is obtained.
TA _SCell = TA _{PCell -2ΔSCell-PCell} PD _{DL- ΔSCell} PD _UL-DL (Formula 20)

You can replace
_{ΔSCell-PCell} PD _DL = _{ΔSCell-PCell} Rx _{DL- ΔSCell-PCell} Tx _DL (Formula 21)
Here, Δ _SCell-PCell Rx _DL is the difference in downlink reception time between the P cell and the S cell, that is, the reception at UE3 of the downlink transmission on the P cell from the eNodeB and the S cell from the eNodeB. The time difference between reception of the above downlink transmission at UE3, and _{ΔSCell-PCell} Tx _DL is the difference in downlink transmission time between P cell and S cell, ie, P to UE3. It is the time difference between the transmission at the eNodeB for downlink transmission on the cell and the transmission at the eNodeB for downlink transmission on the S cell to the UE 3, and the following equation is obtained.
_{TA SCell = TA PCell -2 · (} Δ SCell-PCell Rx DL -Δ SCell-PCell Tx DL) -Δ SCell PD UL-DL ( formula 22)
= TA _PCell- 2 · Δ _SCell-PCell Rx _DL + 2 · Δ _SCell-PCell Tx _DL- Δ _SCell PD _UL-DL (Formula 23)

In other words, the S cell timing advance is
● P cell timing advance ● Difference in downlink reception time between P cell and S cell ● Difference in downlink transmission time between P cell and S cell ● Uplink and downlink on S cell It can be calculated based on the difference in propagation delay between them.

  The P cell timing advance is basically known to both eNodeB and UE3.

  The difference in downlink reception time between the P cell and the S cell is not known at the eNodeB, but can be measured at the UE side.

The downlink transmission time difference _{ΔSCell-PCell} Tx _DL between the P cell and the S cell is known only to the eNodeB and known to UE3, as will become more apparent in the context of FIG. Absent. In the specific embodiment of FIG. 26, _{ΔSCell-PCell} Tx _DL is zero, and in the embodiment of FIG. 27 described later, the downlink transmission time difference is not zero.

  The difference between the propagation delay between the serving cell uplink and downlink is assumed to be negligible for the purposes of the present invention. More specifically, the propagation delay in the uplink and downlink directions is assumed to be the same for each carrier. Simulations performed by 3GPP WG RAN4 provide a result of the simulated propagation delay difference in the case of inter-band carrier aggregation, which results for 97-98 for the same receiving node (ie eNodeB) The difference in propagation timing is smaller than 1 TA step (˜0.5 μs) in the% case, and is smaller than 5 TA step in the 100% case. In the case of a DL and UL carrier pair linked with SIB-2, where the frequency gap between the uplink and downlink is much smaller than the gap between the different frequency bands, this results in The difference in propagation timing between the UL direction and DL direction of a given cell is quite small and can therefore be ignored by the present invention.

  Given the above and considering that the S-cell timing advance is calculated at the eNodeB, the eNodeB should be provided with information that can determine the difference in downlink reception time on the eNodeB side. In that case, the eNodeB has all the information for determining the S cell timing advance relative to the P cell timing advance.

  As a result of the above considerations, one embodiment of the present invention for S-cell uplink time alignment for UE3 is presented below with reference to FIG.

In step 1 of FIG. 35, UE3 receives downlink reception time difference _{ΔSCell-PCell} Rx _DL , in particular, the time when UE3 receives the start of one subframe from the P cell, and UE3 receives the P cell. The time difference between the time of receiving the corresponding beginning of one subframe from the S cell that is closest in time to the subframe received from is measured. Correspondingly, UE3 performs measurements for each of the two S cells to obtain _{ΔSCell1-PCell} Rx _DL and _{ΔSCell2-PCell} Rx _DL . In the current scenario, the difference in downlink reception time is substantially the same for S cell 1 and S cell 2. The difference in downlink reception time for one S cell can be seen in FIG.

In step 2 of FIG. 35, UE3 uses the result of the measurement, ie the difference in downlink reception time _{ΔSCell1-PCell} Rx _DL and _{ΔSCell2-PCell} Rx _DL , preferably using the _PSCH PUSCH. , To eNodeB. Alternatively, since the difference in downlink reception time is the same, UE3 can only transmit one of the two measurements.

In step 3, the eNodeB receives the measurement result and uses it to calculate the S cell timing advance. Since the difference in downlink reception time is the same for both S cells, only one timing advance is calculated that can be used by UE 3 to align the S cell uplink times. Considering the assumption of the present embodiment, _{ΔSCell-PCell} Tx _DL and _ΔSCell PD _UL-DL can be regarded as zero.
TA _SCell = TA _{PCell -2ΔSCell-PCell} Rx _DL (Formula 24)
And can be written concisely.

Thus, the eNodeB uses the received downlink reception time difference _{ΔSCell1-PCell} Rx _DL / _{ΔSCell2-PCell} Rx _DL and the known time advance of the P cell and S cell 1 and S cell 2 The time advance TA _{SCell1 / SCell2} is calculated according to Equation 24.

In step 4, the eNodeB preferably sends TA _{SCell1 / SCell2} to UE3 using a downlink shared channel and MAC control element, which will be described in more detail later.

In step 5, UE3 receives the timing advance information from the eNodeB and starts the downlink radio frame of S cell 1 and S cell 2 in the same way that standard initial timing advance is applied by the UE. In contrast, the timing advance TA _{SCell1 / SCell2} is applied.

  In this way, the UE 3 can align the uplink times of the S cell 1 and the S cell 2 according to the received uplink scheduling permission, and can start uplink transmission on them. The first uplink grant is usually part of the RAR message within the standard RACH procedure. In the present invention, since the RACH procedure is not performed on the S cell, the first uplink grant for the S cell can be sent to the UE 3 via the PDCCH in any way at any time.

UE 3 sends an uplink transmission to the eNodeB using the uplink grant for S cell 1 and S cell 2. This is shown in FIG. 26 for one S cell. UE3 “shifts” the S cell downlink radio frame reception time T _{DL_RX_SCell} by the timing advance value TA _{SCell1 / SCell2} to thereby change the S cell uplink radio frame transmission time T _{UL_TX_SCell} . Set.

Such time aligned uplink transmissions on the S cell are received at the eNodeB at T _{UL_RX_SCell} after a propagation delay PD _{UL_SCell} .

FIG. 27 shows a timing diagram according to another embodiment of the present invention. Compared to the timing diagram of FIG. 26, the difference is that the P cell and the S cell perform downlink transmission at different times. Further, it is assumed that S cell 1 and S cell 2 have the same downlink transmission timing. In other words, there is a difference Δ _{SCell−PCell} Tx _{DL in the} downlink transmission time between the P cell and the S cell, which is no longer zero and is the same in the S cell 1 and the S cell 2.

  The uplink time alignment procedure described above in connection with FIG. 35 can be similarly applied to the scenario illustrated in FIG. 27 in view of the following procedure changes.

UE3 can _measure the difference _{ΔSCell1-PCell} Rx _DL and _{ΔSCell2-PCell} Rx _DL of the downlink reception time, which are the same in S cell 1 and S cell 2 (step 1). The difference in downlink reception time is not only the difference in propagation delay between the P and S cell paths (as in FIG. 26), but in this case the difference in downlink transmission time Δ _SCell-PCell Tx Note that _{DL is} also considered. In this particular embodiment of the invention, the measured downlink reception time difference Δ _SCell-PCell Rx _DL is longer than the difference in propagation delay between the P cell and the S cell, ie, P cell and S cell. The difference in downlink transmission time between cells is longer than _{ΔSCell-PCell} Tx _DL . Such a difference in downlink transmission time is unknown to UE3, i.e. it is transparent.

Thereafter, these measurement results are transmitted to the eNodeB in the same manner as in Step 2 of FIG. The eNodeB calculates the timing advance of S cell 1 and S cell 2, which again has the same timing advance. However, the eNodeB cannot use Equation 7 described with reference to FIG. 26, and needs to additionally consider the difference _{ΔSCell−PCell} Tx _DL in the downlink transmission time as follows. is there.

Starting from Equation 23, the eNodeB uses the following Equation 25 to determine the S cell timing advance in this particular scenario: That is, for the reasons already described, only _ΔSCell PD _UL-DL is set to zero.
TA _SCell = TA _PCell- 2 · Δ _SCell-PCell Rx _DL + 2 · Δ _SCell-PCell Tx _DL (Equation 25)

The determined timing advance TA _{SCell1 / SCell2} is transmitted from the eNodeB to the UE3 in accordance with step 4 shown in FIG. Therefore, UE3 uses the received timing advance value TA _{SCell1 / SCell2} for the start of the downlink radio frame on each _Scell1 and _Scell2 and on _Scell1 and _Scell2 . Align uplink transmission times.

  Even if the eNB knows the timing advance used by the UE for uplink transmission on the P-cell, TS 36.133, section 7.1.2, except just after the PRACH transmission has taken place. It should be noted that the autonomous change by the UE of the uplink timing according to this causes some deviation from the P cell timing advance value signaled from the eNB to the UE. Thus, according to another alternative embodiment, the UE can determine between the DL radio frame received on the P cell and the UL radio frame transmitted on the P cell in addition to the measurement of the difference in downlink reception time. The difference in use is also reported to the eNB.

  In the following, variations and addition steps of the embodiment described above are presented in connection with each step of FIG.

Triggering the reporting step by the UE In the above embodiment, it was not mentioned when the UE started the measurement of step 1 and the reporting of the measurement result of step 2. The measurement can be performed periodically, for example.

  Reporting / signaling can be performed either periodically or event triggered.

  For example, periodic triggering of reports may be similar to reports of mobility or power headroom or buffer status reports. The advantage of periodic reporting is that the eNodeB gets up-to-date information about the measurement results at a specific period. Thus, the eNodeB can calculate the exact timing advance of the S cell at periodic intervals, thereby sending the timing advance to the UE immediately if necessary.

  However, event-triggered reports are equally beneficial and are needed, for example, to allow the eNodeB to react quickly to prevent increased interference due to some erroneous uplink timing. there is a possibility. Several events are described below.

  The configuration of the S cell can be used as a trigger for the UE to start reporting measurement results to the eNodeB. Measurements and reports are made according to one exemplary embodiment with respect to configured and deactivated S-cells. Providing measurement results to the eNodeB each time a new S cell is configured has further advantages. More specifically, the eNodeB has the opportunity to see if different timing advance (multi-TA) is needed for the newly configured S-cell. Furthermore, the eNodeB can already calculate the required timing advance for the S cell, and can optionally signal the timing advance to the mobile terminal. In other words, even if the S cell is deactivated (ie not used for transmission), the mobile terminal already knows which timing advance to use for this S cell. Thus, when the S cell is activated, the mobile terminal can immediately apply the previously received timing advance for the S cell and transmit with the correct uplink time alignment already. Thus, for example, S cell activation is faster when compared to an approach where RACH needs to be performed on the newly activated S cell to achieve uplink synchronization. Basically, the activation delay for the S cell is the same as Rel-10, where the S cell has the same timing advance as the P cell when using the present invention.

  Alternatively, S cell activation may be used by the UE as a trigger to initiate measurement and / or reporting of measurement results. An advantage of using activation as a trigger is that when an eNodeB activates an S cell, the eNodeB also intends to schedule transmissions on the S cell. In order to determine the correct timing advance used for uplink transmission on the activated S-cell, it is beneficial to provide the latest measurement results to the eNodeB.

  Another option to be used as a trigger is that the mobile terminal receives a specific request from the eNodeB to report measurement results to the eNodeB. This allows the eNodeB to determine for each case whether a report of measurement results is necessary. There are several possibilities how to send this request from the eNodeB to the mobile terminal. For example, an RRC message constituting an S cell, for example, a flag in an RRC connection reconfiguration message may explicitly request a report of measurement results.

  Alternatively, the activate / deactivate command (MAC CE) shown in FIG. 20 may include a flag that explicitly indicates the need for timing information reporting, i.e., eNodeB is mobile to report measurement results. Explicitly request from the terminal. The flag may be signaled by using an empty “reserved bit” in the activation / deactivation MAC control element. The activation / deactivation MAC control element actually activates or deactivates any of the S cells since activation of already activated S cells is supported (also called reactivation). Can be sent by the eNodeB at any time to request a report of the measurement results.

  Another possibility is to reuse the so-called “RACH command” message, which is physical layer signaling (PDCCH using DCI format 1A). According to one embodiment, the RACH command itself is used, i.e., the mobile terminal that is requested to create a RACH on the S cell varies from mobile terminal to mobile terminal, i.e., performs a measurement report. Can be interpreted. Alternatively, some predefined code point or field code point combination in the RACH order for the S cell may be used as a report request. For example, a RACH command for an S cell with ra-PreambleIndex set to “000000” (ie, usually indicating that the UE should perform contention based RACH) is re-requested to request a report. Can be defined. Alternatively, a predefined carrier indicator (CI) code point for the case of cross-scheduling can be used as a request. The advantage is that the uplink resource allocation from which the mobile terminal will send the measurement results can be sent together with the measurement and / or report request, thus reducing the report delay.

  Another trigger event for reporting measurement results is that the results of measurements performed in connection with the S cell uplink time alignment may exceed certain preconfigured limits. This is particularly beneficial when the eNodeB does not know the need to use a timing advance for the S cell that is different from the P cell timing advance. The eNodeB does not always have sufficient knowledge from, for example, OAM (operation / management / maintenance that normally provides cell placement information such as the presence of repeaters or RRHs). Also, the need for multi-timing advance depends on the location of the UE (see FIG. 24 and corresponding description). Thus, for example, a frequency selective repeater may be transparent to the eNodeB and is made visible to the eNodeB only by the mobile terminal reporting on large downlink reception time differences. Alternatively, even if the eNodeB is aware of the FSR, the eNodeB does not know exactly when the mobile terminal will no longer receive S-cells via the FSR rather than from the eNodeB.

  Another trigger may be that the timing advance timer that is initiated by the mobile terminal expires when applying an initial timing advance or timing advance update. If the timing advance timer expires, i.e., no timing advance update is received, the mobile terminal may perform one of the various embodiments of the present invention.

Measurement and reporting steps by the UE As described so far, the mobile terminal measures and reports the difference _{ΔSCell-PCell} Rx _DL in downlink reception time between the S cell and the P cell. Alternatively or additionally, the mobile terminal can also measure and report the difference _{ΔSCell−PCell} Rx _DL −Tx _UL in the received transmission time between the P cell and the S cell. As also shown in FIG. 26 or FIG.
_{ΔSCell-PCell} Rx _DL -Tx _UL = T _{DL_RX_SCell} -T _{UL_TX_PCell}
It is.

  In other words, the difference in reception and transmission time between the P cell and the S cell is that the time when the mobile terminal transmitted the uplink radio frame on the P cell and the time when the mobile terminal received the downlink radio frame on the S cell. It is the time difference from the time. Uplink radio frames and downlink radio frames refer to the same radio frame number.

As can be seen from FIG. 26 or FIG. 27, the downlink reception time difference _{ΔSCell-PCell} Rx _DL is _{equal to} the reception transmission time difference _{ΔSCell-PCell} Rx _DL- Tx _UL and the P cell timing advance TA _PCell . Based on, in particular,
_{ΔSCell-PCell} Rx _DL = _{ΔSCell-PCell} Rx _DL- Tx _UL- TA _PCell (Formula 26)
Where TA _PCell can also be replaced by the time measured between _{TUL_TX_PCell} and _{TDL_RX_PCell} . The measurement time between _{TUL_TX_PCell} and _{TDL_RX_PCell} can be reported to the eNodeB along with the difference in reception and transmission time.

  For future techniques such as cooperative multi-point (COMP) transmission in the uplink, the difference in received transmission time can be used to control the timing of the uplink transmission, so that downlink reception Instead of the time difference, it is advantageous to measure and report the difference in reception and transmission time. Furthermore, this may be preferable from the viewpoint of mounting.

In that case, the difference _{ΔSCell−PCell} Rx _DL− Tx _UL in the reception transmission time is reported to the eNodeB, and then the eNodeB uses the equation 26 to _calculate the difference _{ΔSCell−PCell} Rx _DL in the downlink reception time. calculate. As described above and as will be described in more detail later, the eNodeB may calculate the S cell timing advance based on the calculated downlink reception time difference.

  Note that the mobile terminal can count, for example, the number of samples as a way to determine the time difference. For example, in order to calculate the difference in downlink reception time, the mobile terminal calculates the number of samples between the reception time of the downlink subframe in the P cell and the reception time of the downlink subframe in the S cell. Count. For example, a downlink subframe may refer to a common reference signal (CRS).

Report of measurement result After performing the measurement, the mobile terminal transmits the result to the eNodeB. As already explained, the measured value may _{refer to} the difference in downlink reception time Δ _SCell-PCell Rx _DL or the difference in reception transmission time between P cell and S cell Δ _SCell-PCell Rx _DL -Tx _UL There is sex.

  The report itself can in principle be implemented in several layers, for example the RRC layer or the MAC layer. Other measurements such as mobility or location measurements are also signaled at the RRC layer. Since the timing advance command is generated by the MAC layer, it may be beneficial from an implementation point of view to implement the measurement result report in the MAC layer.

  FIGS. 29 and 30 show the format of a MAC control element that can be used to transmit measurement results from the mobile terminal to the eNodeB. As is apparent, the structure of this MAC CE is similar to the extended power headroom MAC CE. The size depends on the number of S cells configured or configured and activated, i.e. the number of S cells on which measurements and reports are to be performed. More particularly, FIG. 29 shows a MAC control element for transmitting the downlink reception time difference between the P cell and all available S cells 1-n.

On the other hand, FIG. 30 shows a MAC control element for transmitting the difference in reception transmission time between the P cell and all available S cells 1 to n. In an alternative embodiment, this information should not be reported to the eNodeB, since the time between T _{UL_TX_PCell} and T _{DL_RX_PCell} corresponds to the TA _PCell and therefore should actually be known by the eNodeB.

  Instead of reporting the downlink reception time difference and reception transmission time difference for all S cells, the mobile terminal may report them only for the specific S cells that are to be timed.

  In addition, the time difference may be encoded and indicated by the number of samples, i.e. the mobile reports a specific number of samples, and then the eNodeB uses the number of samples and the time of the samples to calculate the actual time difference. There is a possibility of deriving.

  As already mentioned before, the measurement results are preferably transmitted on the P-cell physical uplink shared channel, PUSCH.

Determining Timing Advance for S Cell In the above embodiment of the present invention, the eNodeB determines the timing advance value known from the standard RACH procedure, ie, the downlink S as illustrated in FIGS. It was assumed to calculate the timing advance (see arrow TA _SCell ) applied by the mobile terminal relative to the beginning of the downlink radio frame received via the cell. This is because the timing advance value is the same type as the timing advance defined by the standard and is defined relative to the downlink reception of the radio frame of the S cell, not to the P cell. So it may be called an absolute value.

But there are other alternatives. The timing advance calculated by the eNodeB and applied by the mobile terminal need not be relative to the beginning of the downlink radio frame received via the downlink S cell, other criteria selected Can be done. For example, the calculated and applied timing advance is relative to the beginning T _{DL_RX_PCell} of the downlink radio frame received via the P cell, or the uplink transmitted via the P cell. _{May be} relative to the start of _{TUL_TX_PCell} .

If the timing advance is calculated relative to the beginning of the uplink radio frame transmitted over the P cell, basically the timing advance is the timing advance between the P cell and the S cell. Advance difference _{ΔTA PCell-SCell} . Considering Equation 23,
_{ΔTA PCell-SCell} = -2 · Δ _SCell-PCell Rx _DL + 2 · Δ _SCell-PCell Tx _DL -Δ _SCell PD _UL-DL
It is.

Therefore, the timing advance determined by the eNodeB and transmitted to the mobile terminal is _{ΔTA PCell-SCell} . And this time, the mobile terminal applies this value relative to the start of the uplink radio frame received via the P cell, and the uplink for uplink transmission performed on the S cell. Determine the timing. This is illustrated in FIG. 31, where the timing advance is indicated by the number of samples N _TA and the actual to be applied for the uplink transmission in the S cell compared to the uplink transmission in the P cell. Multiply by the sample time T _S to obtain the time difference.

If the timing advance is calculated relative to the start of the downlink radio frame received via the downlink P-cell, the timing advance value can be inferred from FIGS. In addition,
TA _SCell -Δ _SCell-PCell Rx _DL
It is. Accordingly, eNodeB first calculates the timing advance value _{TA SCell,} from the timing advance value _{TA SCell,} catching difference Δ _{SCell-PCell Rx DL} reception time of the received downlink. Thereafter, the calculation result is reported to the mobile terminal, and the mobile terminal is based on the received timing advance relative to the start of the downlink radio frame received by the mobile terminal in the P cell. Set the uplink transmission timing. This is illustrated in FIG. 32, where the timing advance is indicated by the number of samples N _TA and the time of the samples to obtain the actual time difference to apply for uplink transmission in the S cell. It is multiplied by the T _S.

Transmission of timing advance command The calculated timing advance may be transmitted to the mobile terminal using, for example, the downlink shared channel of the S cell to which the timing advance is applied. FIG. 33 illustrates the format of a timing advance command to be used to transmit a calculated timing advance from the eNodeB to the mobile terminal according to one particular embodiment of the invention. If the timing advance information calculated and sent to the mobile terminal is TA _SCell (and is not part of the relative values mentioned above in connection with FIGS. 31 and 32), the initial TA as known from the standard In order to achieve the required granularity (same as command), 11 bits are preferably used to transmit the timing advance for the S cell.

  On the other hand, if the timing advance is smaller, it is relative to another timing, so fewer bits are sufficient.

  One example is to use a new MAC control element to carry timing advance information, eg, 8 bits. Alternatively, a timing advance update command known from LTE Release 8 having the format shown in FIG. 33 may be used. One of the free R bits can be used to distinguish between the actual timing advance update command known from the standard and the timing advance information according to one of the various embodiments of the present invention.

  Since some embodiments use relative timing advance (see description associated with FIGS. 31 and 32), the 6 bits provided by the timing advance update command may provide sufficient granularity. .

  Another alternative is for the eNB to send timing advance information for all configured or configured and activated S cells, not just for one S cell. If the UE reports timing information for all configured or configured and activated S-cells according to the above embodiment, it makes sense to report all calculated TAs accordingly. there is a possibility.

S-cell grouping In the scenario envisaged for FIGS. 24, 34 and 26, S-cell 1 and S-cell 2 have the same propagation delay for S-cell 1 and S-cell 2, so Has advance. In the case described above, S cell 1 and S cell 2 may be said to form a timing advance group.

  In addition to this scenario, there are several configurations, or configurations and actives that form different timing advance groups depending on whether the S cells can be timed on the uplink with the same timing advance value There may be S cells to be converted. As already explained, there are several reasons that lead to the need for different timing advance between different S cells of the same mobile terminal. An example is one or more frequency selective repeaters that amplify only some of the signals in the S cell.

  In any case, when the mobile terminal stores the mapping of the S cell to the specific timing advance group, it is necessary to align the times of the S cells 1 belonging to the timing advance group having the S cell 2 having the same time. When there is a mobile terminal, the mobile terminal can immediately apply the timing advance previously used to the S cell 2 with the same time, and can also adjust the uplink transmission time of the S cell 1. Thus, it is not necessary to perform all the steps of the present invention.

  The mapping of S cells to timing advance groups can only be configured and updated by the eNodeB.

Hardware and Software Implementation of the Invention Another embodiment of the invention relates to the implementation of the various embodiments described above using hardware and software. In this context, the present invention provides a user equipment (mobile terminal) and an eNodeB (base station). User equipment is adapted to perform the methods described herein. Further, the eNodeB determines the power state of each user device from the power state information received from the user device, and considers the power state of different user devices in scheduling of the different user devices by the scheduler of the eNodeB. Includes means to enable.

  It is further appreciated that the various embodiments of the invention may be implemented or performed using computing devices (processors). The computing device or processor is, for example, a general purpose processor, digital signal processor (DSP), application specific integrated circuit (ASIC), field programmable gate array (FPGA), or other programmable logic device. there is a possibility. Various embodiments of the present invention may be implemented or embodied by combinations of these devices.

  Furthermore, various embodiments of the invention may be implemented by a processor or by software modules that are executed directly in hardware. A combination of software module and hardware implementation is also possible. A software module may be stored on any kind of computer readable storage media, for example RAM, EPROM, EEPROM, flash memory, registers, hard disks, CD-ROM, DVD, etc.

  It is further noted that individual features of different embodiments of the invention can be the subject of another invention, either individually or in any combination.

  It will be appreciated by those skilled in the art that many changes and / or modifications can be made to the invention shown in the specific embodiments without departing from the spirit or scope of the invention as broadly described. . Accordingly, these embodiments should be considered as exemplary only and should not be considered limiting.

Report on Differences in Propagation Delays of Multiple Downlink Component Carriers The present invention also provides a method for reporting by a mobile terminal about downlink timing in a mobile communication system, wherein downlink sub-carriers on different serving cells Used to report when the frame transmission and / or reception time difference exceeds a predefined maximum time difference, whereby the aggregation access point detects such a situation for the mobile terminal Make it possible.

  According to a further aspect of the invention, a mobile terminal (referred to as user equipment in 3GPP terminology) aggregates a serving cell via different radio links on different downlink serving cells, said downlink In order to enable the aggregation access point to detect situations where transmissions experience different propagation delays, a report on the downlink timing of the aggregated downlink serving cell is proposed.

  Such an aggregation is used for eNodeB, RRH for co-processing at a mobile terminal protocol entity protocol data units received in transmissions (eg, respective subframes) on different downlink serving cells. Or simultaneous reception of radio signals corresponding to transmissions (eg, respective subframes) on different downlink serving cells from a radio signal transmission node such as an FSR.

  In the following, the term “reference cell” refers to a cell (P cell or one of S cells) used as a reference for the measurement of the downlink timing difference by the mobile terminal. Since the mobile terminal is initially configured for reception via this cell, it is advantageous to make the P cell the reference cell. Nevertheless, any other downlink S cell, for example, the S cell from which a corresponding downlink transmission is first received in time can also be a reference cell, and therefore The cell located closest to the mobile terminal is used as the reference cell. The only requirement is that the eNodeB and the mobile terminal have the same understanding of which serving cell serves as the reference cell, e.g. the eNodeB configures the reference cell and signals its configuration to the mobile terminal. can do.

  The term “target cell” in the following refers to the cell from which the downlink transmission is received by the mobile terminal at a time different from the time of the reference cell and is therefore subject to the reporting procedure of the present invention. According to the definition of “reference cell” above, the “target cell” is most often one of the S cells aggregated by the mobile terminal at a later time. In the special case, i.e., when the mobile terminal is located much closer to the S cell than the P cell and the downlink transmission from the P cell suffers greatly from interference such as jitter or channel fading effects, for example. The P cell may also be the target cell.

  However, the following special scenarios should not be understood as limiting the present invention, but as an example to illustrate the principles of the present invention. It is assumed that the reference cell is a P cell and the target cell is an S cell. It is assumed that the aggregation access point is an eNodeB.

  FIG. 36 shows a signaling diagram illustrating various steps performed by a mobile terminal and an eNodeB and messages exchanged between them to enable a reporting procedure according to one embodiment of the present invention. Yes. The mobile terminal configured a P cell that exchanges data with the eNodeB via it. In particular, the mobile terminal is configured to receive downlink transmissions from the P cell and is aligned in uplink time to allow uplink transmissions to the P cell. Further, the mobile terminal is configured to receive a downlink transmission from the S cell. A mobile terminal may be configured with an uplink cell associated with a downlink S cell, i.e., called an uplink S cell, which is not important for performing the reporting procedure of the present invention. Absent.

  The following steps are performed according to FIG.

  1. The mobile terminal performs measurements to determine specific timing information for transmission / reception in the P cell and / or S cell. As described in more detail below, there are various timing information that can be determined by the mobile terminal. This timing information that the terminal measures is such that the mobile terminal can then determine the difference in propagation delay between the P cell and the S cell. The timing information of the measurement is such that it is not yet known by the eNodeB, and therefore the timing of transmission and / or reception of signal exchanges performed on the P cell and / or S cell between the mobile terminal and the eNodeB. Information related to timing not known to eNodeB.

  2a. The mobile terminal then compares the measurement results with a predefined maximum time difference. The maximum time difference can be predefined for a particular mobile terminal or can be predefined for a mobile communication system including a mobile terminal. In particular, the maximum time difference refers to the propagation delay, ie, the maximum time difference defines the maximum propagation delay difference between the aggregated cells or component carriers. There are various ways in which the comparison can be performed, which are described in detail below. In any case, the mobile terminal can determine whether the measurement result exceeds a predefined maximum propagation delay difference.

  3a. Information regarding the result of the comparison is transmitted to the eNodeB.

  As an alternative to steps 2a and 3a described above, the mobile terminal and eNodeB may also perform the following steps (shown as a dashed line in FIG. 36 as an alternative):

  2b. The result of the measurement is transmitted to the eNodeB by the mobile terminal.

  3b. The eNodeB uses information about the result of the measurement received from the mobile terminal and compares it with a predefined maximum time difference. As explained above, the maximum time difference can be predefined for a particular mobile terminal or can be predefined for a mobile communication system including a mobile terminal. In particular, the maximum time difference refers to the propagation delay, that is, the maximum time difference defines the maximum propagation delay difference. There are various ways in which the comparison can be performed, which are described in detail below. In either case, the eNodeB can determine whether the measurement result exceeds a predefined maximum propagation delay difference.

  There are various advantages provided by the present invention described above.

  First, the eNodeB does not know exactly the propagation delay that affects downlink transmissions to mobile terminals using different paths. Even if the eNodeB or more specifically the carrier knows about the deployment and should be able to have some view (estimation) on the propagation delay for different serving cells based on this information, specifically , Transmission timing imperfections at network transmission points (eNodeB, RRH), i.e., clock drift between different transmission points, resulting in greater downlink reception time difference between serving cells The timing of downlink reception at the mobile terminal changes due to inaccuracy of the clock that generates the signal, or due to channel effects such as fading. Thus, the downlink timing report provides the eNodeB with additional information that allows the serving cell to be reconfigured.

  Furthermore, as explained at the end of the background section, mobile terminals may be provided with limited reception capabilities. In particular, the mobile terminal may have a limited size receiver window that allows simultaneous processing of downlink transmissions. Nevertheless, reception of downlink transmissions on different aggregated downlink serving cells requires joint processing by the mobile terminal. Therefore, the downlink timing report is a situation where the mobile terminal's limited reception capability prevents the mobile terminal from successfully receiving downlink transmissions of multiple aggregated serving cells, i.e., by the mobile terminal. The eNodeB detects a situation where a serving cell (S cell) with a relative propagation delay difference larger than the supported reception window size (compared to the reference cell) may not be decoded correctly by the mobile terminal. Make it possible.

  In the following, more specific embodiments of the present invention will be described.

  For example, assume a scenario in which a UE (mobile terminal) is configured with a P cell served by an eNodeB and an S cell served by an RRH, as in FIG. It can be assumed that P-cell coverage is greater than S-cell coverage.

  In this scenario, the UE may be positioned at the P cell coverage boundary and the S cell coverage boundary such that the propagation delay for the P cell downlink transmission is greater than the propagation delay for the S cell downlink transmission. May happen. Thus, the UE receives the P cell downlink subframe from the eNodeB at a later time than receiving the corresponding S cell subframe from the RRH.

  In this particular scenario, whether a report on downlink timing is needed to achieve the benefits mentioned above depends on the location of the UE. More specifically, depending on the location of the UE composed of P-cells served by eNodeB and S-cells served by RRH, the downlink timing depends on the difference in reception time that can be ignored ( For example, if the UE is positioned between eNodeB and RRH) and the difference in reception time that is large for the corresponding subframe (eg, if the UE is not positioned between eNodeB and RRH) To do.

  A similar exemplary scenario for a UE configured with a downlink P-cell served by an eNodeB and a downlink S-cell repeated by an FSR was described with respect to FIG. Again in this scenario, whether downlink timing reports are needed to achieve the benefits mentioned above depends on the UE location.

In this more specific embodiment, it is assumed that both the P cell and the S cell transmit subframes to the UE on the downlink at the same time. Downlink transmission is performed at the same time, but the P cell and S cell have different propagation delays (PD _{DL_PCell} , PD _{DL_SCell} ), so reception of the downlink transmission by the UE is not simultaneous (T _{DL_RX_PCell} , T _{DL_RX_SCell} ) .

Referring to FIG. 26 illustrating exemplary reception and transmission timing of frames transmitted on the P cell and S cell, the difference in propagation delay of downlink transmission (Δ _SCell-PCell Rx _DL ) is It must be noted that it can be measured by the method.
_{ΔSCell−PCell} Rx _DL = T _{DL_RX_PCell} −T _{DL_RX_SCell} (Formula 27)
= ( _{TUL_TX_PCell} - _{TDL_RX_PCell} )-( _{TUL_TX_PCell} - _{TDL_RX_SCell} ) (Formula 28)

Thus, the UE measures the time difference between the reception of the beginning of the first downlink subframe on the target cell (T _{DL_RX_SCell} ) and the reception of the corresponding downlink subframe on the reference cell (T _{DL_RX_PCell} ). (In other words, by applying Equation 27 above), the difference in downlink reception time ( _{ΔSCell−PCell} Rx _DL ) can be determined.

Alternatively, the UE is between the time when the UE transmitted an uplink radio frame on the reference cell (T _{UL_TX_PCellll} ) and the time when the UE received the downlink radio frame on the target cell (T _{DL_RX_SCelll} ). By measuring the time difference, the difference in downlink reception time (Δ _SCell-PCell Rx _DL ) can be determined. If the UE measures the time difference between the transmission on the reference cell and the reception on the reference cell and the target cell, the downlink reception time difference (Δ _SCell-PCell Rx _DL ) is equal to the transmission on the reference cell. Can be determined by subtracting the time difference between the transmission on the reference cell and the reception on the target cell (ie applying Equation 28 above) from the time difference between the reception on the reference cell. .

In other words, the transmission and / or reception time difference information is
● Downlink reception time difference between P cell and S cell (Δ _SCell-PCell Rx _DL ), or ● Reception reception time difference between P cell and P cell / S cell (Δ _SCell-PCell Rx _DL) -Tx _UL )
Can be measured as

  The difference in downlink reception time between the P cell and the S cell is not known at the eNodeB, but can be measured at the UE side.

  As a result of the above discussion, a more detailed embodiment of the present invention for reporting downlink timing is presented in connection with FIG.

In Step 1 of FIG. 36, the UE determines that the UE receives the difference in downlink reception time (Δ _{SCell−PCell} Rx _DL ), and in particular, the time when the UE receives the start of one subframe from the P cell and the UE The time difference between the time when the corresponding start of one subframe from the S cell corresponding to the same subframe number as the subframe received from the cell is received is measured.

In addition or alternatively in step 1, the UE transmits information on the difference in received transmission time (Δ _SCell-PCell Rx _DL -Tx _UL ) and, in particular, the UE has transmitted an uplink radio frame on the P cell. The time difference between the time and the time at which the UE received the downlink radio frame on the S cell can also be measured, and the uplink radio frame and the downlink radio frame are related to the same radio frame. In addition, the UE also measures the time difference between the uplink timing on the P cell and the downlink reception timing on the P cell. This measured received transmission time difference on the P-cell (Δ _PCell-PCell Rx _DL -Tx _UL ) should be known by both the UE and eNB by the UE for uplink transmission on the P-cell. Even if it basically corresponds to the timing alignment (TA) value used, it is up according to TS 36.133, section 7.1.2, except just after receiving the timing adjustment command during the RACH procedure. An autonomous change of the link timing by the UE causes a certain deviation from the TA _PCell . Thus, further reporting of such values to the eNodeB is beneficial but not essential.

In step 2a of FIG. 36, the UE _compares the measurement result, that is, the difference in downlink reception time ( _{ΔSCell−PCell} Rx _DL ) with a predefined maximum propagation delay time difference (Δ _max T _prop ). In particular, the UE _{compares the} downlink reception time difference (Δ _SCell-PCell Rx _DL ) with a predefined propagation delay time difference (Δ _max T _prop ) that defines the maximum reception time difference for the UE. .

Additionally or alternatively, in step 2a, UE, in order to determine the difference between the reception time of the downlink _{(Δ SCell-PCell Rx DL)} , the measured value of the difference of the received transmission time (Δ _SCell-PCell Rx it is also possible to use _DL -Tx _UL) and measurements of the difference between the received transmission time on P cell _{(Δ PCell-PCell Rx DL -Tx} UL) for comparison step. The UE then determines the difference in the received downlink time (Δ _{SCell−PCell} Rx _DL ) as the pre-defined maximum propagation delay time difference (Δ _max T _prop ) that defines the maximum reception time difference for the UE. ).

If the comparison result of step 2a in FIG. 36 indicates that the measurement result exceeds the predefined maximum propagation delay time difference (Δ _max T _prop ), the UE further proceeds to step 3a in FIG. . If the comparison result indicates that the measurement result does not exceed a predefined maximum propagation delay time difference (Δ _max T _prop ), the UE may determine the timing of reception on the aggregated downlink cell. Assuming joint processing by the UE is enabled, step 3a of FIG. 36 is not executed.

  In step 3a of FIG. 36, the UE transmits the result of the comparison, for example, the external maximum propagation delay time difference value to the eNodeB, preferably by using the PSCH PUSCH.

Additionally or alternatively, in step 3a of FIG. 36, the UE determines the result of the measurement, ie the difference in downlink reception time (Δ _{SCell−PCell} Rx _DL ) and / or the difference in reception transmission time (Δ _SCell). the _-PCell Rx _DL -Tx _UL), together with differences in the receiving transmission time on P cell _{(Δ PCell-PCell Rx DL -Tx} UL) optionally, be sent to the eNodeB.

  Instead of steps 2a and 2b described above, the UE and eNodeB may also perform the following steps (shown as dashed lines in FIG. 36 as an alternative):

In step 2b of FIG. 36, the UE _transmits the measurement result, ie, the difference in downlink reception time (Δ _SCell-PCell Rx _DL ) to the eNodeB, preferably by using the _PSCH PUSCH.

Additionally or alternatively, in step 2b of FIG. 36, the UE may use the received transmission time difference ( _{ΔSCell−PCell} Rx _DL −Tx _UL ) as a result of the measurement, optionally receiving transmission on the P cell. Along with the time difference (Δ _{PCell−PCell} Rx _DL −Tx _UL ), it is preferably transmitted to the eNodeB by using the PSCH PUSCH. In particular, when transmitting the difference (Δ _SCell-PCell Rx _DL -Tx _UL ) and (Δ _PCell-PCell Rx _DL -Tx _UL ) of the reception transmission time, the UE uses the PUSCH of the reference cell (P cell). The difference between the reception and transmission times can be transmitted together.

In step 3b of FIG. 36, the eNodeB receives the measurement result and compares it with a predefined maximum propagation delay time difference (Δ _max T _prop ). In particular, the eNodeB _compares the received downlink reception time difference (Δ _SCell-PCell Rx _DL ) with the maximum propagation delay time difference (Δ _max T _prop ), which defines the maximum reception time difference for the UE.

Additionally or alternatively, in step 3b, the eNodeB may measure the measured received transmission time difference ( _{ΔSCell−PCell} Rx _DL −Tx _UL ), optionally measuring the received transmission time difference on the P cell. Received together with the value (Δ _{PCell−PCell} Rx _DL −Tx _UL ) and based on them, the difference in downlink reception time (Δ _{SCell−PCell} Rx _DL ) is determined. The eNodeB then _compares the determined downlink reception time difference (Δ _SCell-PCell Rx _DL ) with the maximum propagation delay time difference (Δ _max T _prop ), which defines the maximum downlink reception time difference for the UE. To do.

As a result, by performing either of the above-described steps 1, 2a and 3a, or the above-mentioned steps 1, 2b and 3b, the UE will have an aggregated downlink serving cell, i.e. P cell. And information on the downlink timing of the S cell is provided to the eNodeB. In particular, the eNodeB has aggregated downlink serving cells, i.e. P and S cell downlink timings, that have a predefined maximum propagation delay difference (Δ _max T _prop ) for the UE. Provided with information that indicates whether or not it has been exceeded.

  In the following, variations and further steps of the embodiment described above are presented in connection with FIG.

  In the embodiment described above, a procedure for reporting downlink timing has been described in order to provide the eNodeB with additional information regarding the downlink timing of the serving cell aggregated by the mobile terminal. In the following more detailed embodiment, a procedure for reporting on downlink timing used for mobile terminal reconfiguration is described.

  According to the first variant, in step 4a of FIG. 36, the eNodeB determines that the aggregated downlink serving cell, ie the P cell and S cell downlink timing, has a predefined maximum propagation. When it is detected that the delay difference has been exceeded, an S cell deactivation message may be sent to the mobile terminal (UE). In some embodiments, the timing of the downlink exceeding the maximum propagation delay difference may cause the mobile terminal to have a relative propagation compared to the reference cell that is the aggregated serving cell (greater than the defined maximum). Deactivation of the target cell, i.e. S cell, immediately improves the failure of the mobile terminal, as it prevents the successful reception of the downlink transmission of the serving cell with the differential delay.

  In another variation, in step 4b of FIG. 36, the eNodeB reports that the timing of reception of the mobile terminal reporting on downlink timing no longer exceeds the predefined maximum propagation delay difference for the mobile terminal. The downlink time of the target cell, that is, the S cell can be aligned.

In particular, the eNodeB transmits the difference in transmission time between the start of transmission of the downlink subframe on the reference cell (T _{DL_TX_PCell} ) and the start of transmission of the corresponding downlink subframe on the target cell (T _{DL_TX_SCell} ). Can change the timing of downlink transmission on the target cell, ie, the S cell, to reflect the difference in downlink reception time measured by the mobile terminal ( _{ΔSCell-PCell} Rx _DL ), Downlink subframes point to the same subframe number. Specifically, by aligning the time of the downlink transmission on the target cell, i.e., the S cell, eNodeB allows the mobile terminal to elapse faster than the corresponding downlink transmission on the reference cell, i.e., the P cell. Can be reduced or eliminated. This variation can result in serving cell timing similar to that shown in FIG.

Maximum Propagation Delay Time Difference In the above embodiment, how the maximum propagation delay difference is set has not been mentioned. The maximum propagation delay difference value is simply described as a predefined value for a mobile terminal or a predefined value for a mobile communication system including a mobile terminal.

  In a particular variation, the maximum propagation delay difference is derived from system constraints according to which joint processing of downlink subframes received via different aggregated serving cells is no longer possible or practical. Can do. Assuming a large propagation delay difference in a mobile communication system, the mobile terminal's response behavior is also degraded because only uplink transmissions are possible after successful reception from all aggregated downlink serving cells. .

  Further, the maximum propagation delay difference can be derived dynamically by the system provider to meet the service specific reception timing requirements for serving cell aggregation according to another variant. Furthermore, by predefining a constrained maximum propagation delay difference, the service provider can prevent the mobile terminal from aggregating serving cells that are far away.

  According to yet another variant, the maximum propagation delay difference can be derived from mobile terminal (UE) constraints. In particular, the mobile terminal includes a reception time window (receiver window) for the corresponding downlink subframes on the aggregated serving cells, i.e. P and S cells. A receive time window (receiver window) is a receive buffer for temporarily storing serving cell data for relative time differences between aggregated serving cells for processing by the mobile terminal. Since the storage capacity of the reception buffer corresponding to is limited for economic reasons, the maximum propagation delay time difference can be predefined to reflect the reception time window (receiver window). According to one embodiment, the maximum propagation delay difference can be set to be equal to the size of the receive window, ie in Rel-10 3GPP, the UE has a relative propagation delay of 31.3 μsec. A reception window that can handle the difference must be supported. However, in some variations, the maximum propagation delay difference may be set to a value lower than the supported UE reception window size, ie, 90% of the UE reception window size. In this case, the UE can alert the eNodeB before the relative propagation delay difference actually exceeds the UE's receiver requirements (UE reception window), so that due to the large propagation delay difference, Avoid situations where the UE cannot decode the serving cell data.

  According to one embodiment of the invention, the eNodeB sets the maximum propagation delay difference used by the mobile terminal for comparison purposes, ie RRC signaling is used for setting the maximum propagation delay difference value. .

Triggering the reporting step for downlink timing by the UE In the above embodiment, when the UE starts the measurement of step 1 of FIG. 36 and the reporting of the downlink timing of step 2a or 2b. I couldn't touch it. The measurement can be performed periodically, for example.

  Reporting / signaling can be performed either periodically or in an event triggered manner.

For example, periodic triggering of the reporting procedure may be similar to reporting mobility or power headroom or buffer status reports. The advantage of periodic reporting is that the eNodeB has exceeded the predefined maximum propagation delay difference (Δ _max T _prop ) when the downlink timing of the aggregated serving cell, ie, P cell and S cell Receiving the latest information indicating to the mobile terminal. Thus, the eNodeB is aggregated with a difference in downlink reception time (Δ _{SCell−PCell} Rx _DL ) that is excessive, ie exceeding the predefined maximum propagation delay time difference (Δ _max T _prop ). You will be informed whether the mobile terminal will prevent the mobile terminal from successfully processing downlink transmissions on the downlink serving cell, so that you can respond immediately when needed.

However, event-triggered reports are also useful, for example because of the difference in downlink reception time (Δ _SCell-PCell Rx _DL ) that exceeds the predefined maximum propagation delay time difference (Δ _max T _prop ). This may be necessary to allow the eNodeB to react quickly so that the processing of downlink transmissions on the aggregated downlink serving cell is not unsuccessful. Several events are described below.

The configuration of the S cell may be used by the UE as a trigger to initiate a procedure for reporting to the eNodeB about downlink timing. Measurements, comparisons, and optionally reporting are performed according to one exemplary embodiment with respect to configured and deactivated S-cells. When reporting to the eNodeB about downlink timing, there is an additional advantage when a new S-cell is configured. More specifically, the eNodeB allows the mobile terminal to successfully handle downlink transmissions on aggregated downlink serving cells due to excessive downlink reception time difference (Δ _SCell-PCell Rx _DL ). Have the opportunity to check before activating the S-cell to prevent it from doing so. Thus, when the S cell is activated, the eNodeB can assume that the mobile terminal can successfully handle downlink transmissions on the aggregated downlink serving cell.

Alternatively, S-cell activation may be used by the UE as a trigger to initiate a procedure for reporting to the eNodeB about downlink timing. An advantage of using activation as a trigger is that when an eNodeB activates an S cell, the eNodeB also intends to schedule transmissions on the S cell. In addition, the eNodeB triggers measurements, comparisons, and optionally reports through S-cell activation, so that the eNodeB has an excessive downlink reception time difference (Δ _SCell-PCell Rx _DL ) There is an opportunity to check before transmitting downlink data on the S cell whether it prevents the mobile terminal from successfully processing downlink transmissions on the aggregated downlink serving cell.

  Another option to be used as a trigger is that the mobile terminal receives a specific request from the eNodeB to initiate a procedure for reporting to the eNodeB about downlink timing. This allows the eNodeB to determine for each case whether a report on downlink timing is required. There are several possibilities how to send this request from the eNodeB to the mobile terminal. For example, an RRC message constituting an S cell, for example, a flag in an RRC connection reconfiguration message may explicitly request a report of measurement results.

  Alternatively, the activate / deactivate command (MAC CE) shown in FIG. 20 may include a flag that explicitly indicates the need for a reporting procedure, ie, the eNodeB reports to the eNodeB about downlink timing. Explicitly request the start of the procedure. The flag may be signaled by using an empty “reserved bit” in the activation / deactivation MAC control element. The activation / deactivation MAC control element actually activates or deactivates any of the S cells since activation of already activated S cells is supported (also called reactivation). Can be transmitted by the eNodeB at any time without having to.

  Another possibility is to use a so-called “RACH command” message, which is physical layer signaling (PDCCH with DCI format 1A). According to one embodiment, the RACH command itself is used, i.e., the mobile terminal that is requested to create the RACH on the S cell is different for each mobile terminal, i. Can be interpreted to initiate a procedure to Alternatively, some predefined code point or field code point combinations in the RACH order for the S cell may be used as a report request. For example, a RACH command for an S cell with ra-PreambleIndex set to “000000” (ie, usually indicating that the UE should perform contention based RACH) is re-requested to request a report. Can be defined. Alternatively, a predefined carrier indicator (CI) code point for the case of cross-scheduling can be used as a request. The advantage is that the uplink resource allocation from which the mobile terminal will send measurement results and / or comparison results can be sent together with measurement, comparison and / or report requests, thus reducing the report delay. It is to reduce.

  Another triggering event for reporting to the eNodeB about downlink timing may be that the measurement result performed by the mobile terminal has exceeded some pre-set limit, i.e. the maximum propagation delay time difference. it can. This is particularly beneficial when the eNodeB does not know that the downlink reception time difference between the P and S cells has exceeded some preset limit. The eNodeB does not always have sufficient knowledge from, for example, OAM (operation / management / maintenance that normally provides cell placement information such as the presence of repeaters or RRHs), and the eNodeB Channel effects such as clock drift during (eNodeB, repeater, or RRH) or fading are also not known.

Report of measurement result After the mobile terminal performs the measurement, the mobile terminal can transmit the result to the eNodeB. As already explained, the measured values are the difference in downlink reception time Δ _SCell-PCell Rx _DL , or the difference in reception transmission time between P and S cells Δ _SCell-PCell Rx _DL -Tx _UL and any There is a possibility that the selection indicates a difference in reception transmission time on the P cell (Δ _{PCell−PCell} Rx _DL −Tx _UL ).

The report itself can in principle be implemented in several layers, for example the RRC layer or the MAC layer. Other measurements such as mobility or location measurements are also signaled at the RRC layer. According to one embodiment, the difference between the timing measurements Δ _SCell-PCell Rx _DL , or Δ _SCell-PCell Rx _DL -Tx _UL and optionally the reception transmission time on the P cell is on the RRC layer, ie RRC. Reported with signaling. In addition to measuring the timing of reception / transmission, the UE can also report reporting location information to enable improved network operation. Since other timing commands are generated by the MAC layer, it may be beneficial from an implementation point of view to also report on downlink timing at the MAC layer.

  FIGS. 29 and 30 show the format of a MAC control element that can be used to transmit measurement results from the mobile terminal to the eNodeB. As is apparent, the structure of this MAC CE is similar to the extended power headroom MAC CE. The size depends on the number of S cells configured or configured and activated, i.e. the number of S cells on which measurements and reports are to be performed. More particularly, FIG. 29 shows a MAC control element for transmitting the downlink reception time difference between the P cell and all available S cells 1-n.

On the other hand, FIG. 30 shows a MAC control element for transmitting the difference in reception transmission time between the P cell and all available S cells 1 to n. The MAC control element may additionally include a difference in reception transmission time on the P cell (Δ _{PCell−PCell} Rx _DL −Tx _UL ). Alternatively, since the time between T _{UL_TX_PCell} and T _{DL_RX_PCell} corresponds to TA _PCell and therefore should actually be known by the eNodeB, in an alternative embodiment this information should not be reported to the eNodeB. Don't be.

  Instead of reporting the downlink transmission time difference and the reception transmission time difference for all S cells, the mobile terminal can determine whether the downlink transmission time difference and the reception transmission for a particular S cell that exceeds the maximum propagation delay difference. Only time differences can be reported.

  In addition, the time difference may be encoded and indicated by the number of samples, i.e. the mobile reports a specific number of samples, and then the eNodeB uses the number of samples and the time of the samples to calculate the actual time difference. There is a possibility of deriving.

  As already mentioned before, the measurement results are preferably transmitted on the P-cell physical uplink shared channel, PUSCH. However, it is also possible to report the measurement results on the S cell.

Report of comparison result After performing the comparison, the UE transmits the result of the comparison, that is, the external maximum propagation delay time difference value to the eNodeB. As previously described, the comparison is based on the difference in downlink reception time (Δ _{SCell−PCell} Rx _DL ) or the difference in reception transmission time between P and S cells (Δ _{SCell−PCell} Rx _DL −Tx). _UL ), and a predefined maximum propagation delay difference (Δ _max T _prop ).

  The report itself uses a different signaling layer, in principle, using predefined values such as, for example, predefined power headroom report PHR values or predefined channel state information CSI values Can be implemented. In the first case, a report using a predefined PHR value requires that the UE be configured on the uplink on the S cell where the report is performed. In the latter case, reports that use predefined CSI values do not require the UE to be configured on the uplink on the S cell.

  For example, the mobile terminal is predefined to indicate that a component carrier or serving cell has a propagation delay difference with respect to a reference cell, i.e. a so-called virtual PHR, using a predefined code point. PHR values can be used. Virtual PHR relates to the situation where power headroom is calculated for a serving cell that does not have uplink resource allocation, ie, PUSCH / PUCCH transmission, in the corresponding subframe. In such a situation, a predefined PUSCH / PUCCH resource allocation is used for power headroom calculation. One feature of virtual PHR is that it cannot be negative. In other words, for a predefined PUSCH / PUCCH resource allocation, ie 1 RB allocation, the assumed PUSCH / PUCCH never exceeds the maximum transmission power of the component carrier. Therefore, the virtual PHR code points representing negative values (negative dB values) are not allocated and can therefore be reused for other signaling purposes.

  According to one variant of the invention, the mobile terminal reports a negative for the serving cell to the eNodeB that the propagation delay difference relative to the reference cell has exceeded a predefined maximum propagation delay difference. Use the predefined code point of the virtual PHR that represents the value.

  In another variation, similar to using a predefined PHR value, i.e., more specifically a predefined code point of the virtual PHR, the mobile terminal (UE) In order to inform the eNodeB about the serving cell received outside the window, i.e. the difference in propagation delay relative to the reference cell exceeds the maximum value, the predefined code points of the CSI report are used.

  In a further variation of the present invention, the mobile terminal (UE) reports “out of range” using a specific CQI code point for component carriers received outside the receiver window of the UE.

  In yet another variation, the mobile terminal may include a CSI code combined with a rank indicator that indicates a rank greater than 1 to indicate “exceeding maximum propagation delay difference” for CQI, eg, “out of range”. Use a combination of points. Other combinations of CSI code points are possible.

  As already mentioned before, the measurement results are preferably transmitted on the physical uplink shared channel PUSCH of the P cell.

UE behavior when a serving cell is received outside the UE's receiver window According to another more detailed embodiment of the invention, the serving cell is not received within the UE's receiver window, i.e. Describes UE behavior when aggregated serving cell data cannot be decoded correctly due to the fact that the propagation delay difference relative to the reference cell is too large and exceeds the UE receiver window length. The

  The signaling means mentioned above, for example timing measurement reports, or special CSI or PHR code points are mainly used to avoid situations where certain aggregated serving cells are not received within the receiver window. Even if used, such signaling is also used to indicate to the eNodeB that the serving cell propagation delay difference has already exceeded the UE's receiver window and therefore cannot be decoded correctly by the UE. Note that it can be used.

  In addition or alternatively, according to a further more detailed embodiment of the present invention, the UE is on an uplink cell in which the associated downlink cell is received outside the UE's receiver window. , Stop sending PUSCH and / or SRS. Since the eNodeB may not know that the propagation delay difference of the serving cell relative to the reference cell exceeds the length of the supported UE receiver window, the eNodeB may Uplink transmissions may still be scheduled above, for example, uplink transmissions may then be scheduled from another serving cell that may be received from the mobile (cross-carrier scheduling).

  According to this embodiment of the invention, the UE ignores uplink grants received for serving cells received outside the UE's receiver window. The eNodeB can detect that there is no scheduled PUSCH transmission on the serving cell / component carrier and recognizes that this serving cell may have problems.

  Similarly, the mobile terminal stops transmitting periodic SRS on the cell received outside the receiver window. The UE may not be able to correctly decode data from the downlink cell (due to timing), and the mobile terminal may serve as a timing reference cell for uplink transmission on the corresponding uplink cell and / or It is also not possible to use this downlink cell as a path loss criterion for uplink power control.

Hardware and Software Implementation of the Invention Another embodiment of the invention relates to the implementation of the various embodiments described above using hardware and software. In this context, the present invention provides a user equipment (mobile terminal) and an eNodeB (base station). User equipment is adapted to perform the methods described herein. Further, the eNodeB determines the power state of each user device from the power state information received from the user device, and considers the power state of different user devices in scheduling of the different user devices by the scheduler of the eNodeB. Includes means to enable.

  It is further appreciated that the various embodiments of the invention may be implemented or performed using computing devices (processors). The computing device or processor is, for example, a general purpose processor, digital signal processor (DSP), application specific integrated circuit (ASIC), field programmable gate array (FPGA), or other programmable logic device. there is a possibility. Various embodiments of the present invention may be implemented or embodied by combinations of these devices.

  Furthermore, various embodiments of the invention may be implemented by a processor or by software modules that are executed directly in hardware. A combination of software module and hardware implementation is also possible. A software module may be stored on any kind of computer readable storage media, for example RAM, EPROM, EEPROM, flash memory, registers, hard disks, CD-ROM, DVD, etc.

  It is further noted that individual features of different embodiments of the invention can be the subject of another invention, either individually or in any combination.

  It will be appreciated by those skilled in the art that many changes and / or modifications can be made to the invention shown in the specific embodiments without departing from the spirit or scope of the invention as broadly described. . Accordingly, these embodiments should be considered as exemplary only and should not be considered limiting.

Claims (5)

A mobile terminal for aligning uplink transmission times in a mobile communication system, the first radio cell including a downlink component carrier and a time aligned uplink component carrier for the mobile terminal; And a second radio cell including a downlink component carrier and an uplink component carrier that is out of time,
Receiving for transmission of downlink from an aggregation access point to the mobile terminal via the downlink component carrier of the first radio cell and the downlink component carrier of the second radio cell, respectively. A processing unit for determining a time difference or a propagation delay difference, the timing advance for the uplink transmission on the uplink component carrier of the first radio cell aligned and the determination The uplink component of the second radio cell by adjusting a timing advance for transmission of the uplink on the uplink component carrier of the second radio cell based on the received reception time difference・ Career time A processing unit to align,
Simultaneously arrives at the aggregation access point via the time aligned uplink component carrier of the first radio cell and the time aligned uplink component carrier of the second radio cell. A transmitter unit for transmitting uplink transmissions to the aggregation access point; and
With
The maximum value of the reception time difference is less than or equal to the reception time window set in the mobile terminal,
mobile computer. While the downlink component carrier and the uplink component carrier of one of the radio cells are established between the aggregation access point and the mobile terminal, the other radio The downlink component carrier and the uplink component carrier of a cell are established between another access point and the mobile terminal;
Bi-directional to the aggregation access point, wherein the other access point transmits transmission from the mobile terminal to the aggregation access point and transmission to the mobile terminal to the mobile terminal Has an interface,
The another access point is a frequency selective repeater (FSR) or a remote radio head (RRH) controlled by the aggregation access point, and the aggregation access point is an eNodeB;
The mobile terminal according to claim 1. The timed uplink component carrier of the first radio cell causes the mobile terminal and access point to set the timing advance for the uplink component carrier of the first radio cell Timed by performing random access procedure,
The mobile terminal according to claim 1 or 2. The processing unit has a given subframe number and determines the arrival time of the start of the subframe received via the downlink component carrier of the second radio cell in the same given subframe. A difference in the reception time or the propagation delay by subtracting from the arrival time of the next beginning of the subframe received via the downlink component carrier of the first radio cell Calculate
The mobile terminal as described in any one of Claim 1 to 3. The mobile terminal has a respective timing advance value for each uplink component carrier or a respective timing advance value for each group of one or more uplink component carriers. ,
Uplink transmissions on the one or more uplink component carriers of the group incur the same propagation delay;
The mobile terminal as described in any one of Claim 1 to 4.

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